Veganics are amazing. I think this is a phenomenal forum and after 2 years people are still interested. I saw a few recent post about soiless mixes for veganics, from personal experience I can definitely say that promix HP and BioBizz coco are great vegan soiless mixes that should go very well with any quality fertilizer schedule, But especially well with any molasses based organic nutrient such as bioCanna or BioBizz. I have personally used bioCanna but prefer the BioBizz line. One way to amend the promix that I've found to work incredibly well is with two bags of BioBizz light mix for every large bale of promix. (the light mix might contain earthworm castings - Im not 100% sure.) The Light mix is soiless for the most part and it provides an amazing organic backbone and some additional stability (great for people who are still trying to dial in their method) in your media, but it is not necessary.
However in defense of worm castings in veganics, it has been suggested that earthworms evolved around the same time as flowering plants
http://en.wikipedia.org/wiki/Annelid under evolutionary history. This seems to hint that the two may have co evolved (in order for plants to produce their maximum each year they need a way to break down discarded produce and vegetable matter quickly, in comes earthworms to maintain a good thermal dynamic, collect remote water, aerate any compacted soil, leave their waste in an ideal form for the plant, etc.. This leads to better preforming plants, which will produce more vegetable matter providing more food for worms who are able to provide more nutrients to the land each year and provide a better substrate for stronger preforming more nutrient demanding plants to succeed). Since we are dealing with flowering plants I don't think the possibility of this relationship should be ignored. Also, Biobizz feeds a mineral/plant diet to their worms, has great control over consistency in their input/output, and earthworms are a great way to transform mineral content in the soil into organic material containing high nutrient content. As far as BioBizz's organic standards, I think the website speaks for itself....
http://www.biobizz.com/us/company/certifications.
There probably are ways to use peat humus in place of the castings if you wanted to try some personalized mixes, but I don't think you will be able to get the same kind of mineral nutrients into the peat humus without significant fermentation time. Another important distinction between earthworm castings and other animal manures is the type of microbes in your grow media that each encourages. Earthworms have incredible bacteria inside their digestive tract, and since they scour through tons of dirt to collect their food these bacteria are very good at removing almost all nutrition from the soil and leaving behind minerals stored in an organic form that is perfect for beneficial fungi to uptake. Larger animals and birds excrete waste that still contains large amounts of organic material that bacteria can feed on. The biggest indication of this difference is normally seen in the Nitrogen level of each product. Castings have little to no Nitrogen, and guano and manures often times must be well composted to prevent burn (usually from excessive nitrogen) and even after composting still contain high nitrogen.
So, earthworm castings can lead to a more fungal dominated soil system and higher animal's waste can initially contribute to a more bacterially dominated soil. Now, bacteria play a significant role in nutrient acquisition for plants but are limited by soil moisture levels and physical distance in their mobility. This in turn limits the volume of organic material that bacteria can digest. Mycorrhizal fungi grow hyphae that can extend throughout the substrate and cover significantly more surface area than would be possible for bacteria to feed on, especially once predatory protozoa begin to feed on larger bacteria populations. In addition to the larger surface area for nutrient uptake myc also provides an incredible increase in mineral uptake, especially minerals that may be in organic or various precipitated forms in the media.
Possibly the most significant role of mycorrhizae in mineral uptake is the increased uptake of Phosphorous in organic form. If ionic Phos is available in the media the plant will not make the appropriate interface for myc symbiosis. Once Ionic phos is gone from the media certain enzymes activate and new gene expressions turn on allowing the myc to infect the root. The main reason for only allowing the interface once ionic P is depleted is that the plant will exude carbohydrates in exchange for minerals (i.e. it will trade sugars made during photosynthesis for minerals the myc has mined from the media). If the plant can aquire "free" (ionic) P then it will not sacrifice hard earned sugars for no reason. However, there is a much higher rate of phosphorous uptake from the media once symbiosis has occurred even if ionic Phos is introduced. Also, ionic phos (and other elements) will oxidize into phosphates (in the case of phosphorus) as the media dries and these are more difficult for the plant to access alone.
Fungal dominance in organic soil leads to a higher rate of mineral acquisition and healthier plants. It is easier with veganics in general to create an environment that is much more suitable for fungal dominance due to the method's dependence on minerals and plant based food sources that are, in nature, less nutritionally dense than animal derived products and certainly less concentrated and/or available than chemical based fertilizers. In general, Earthworm castings help to establish fungal dominance and animal waste/animal products help to establish bacterial dominance. So castings aren't necessary in veganics, but they also don't seem to violate the veganic growing principles.