have you read all of this?

http://www.wetwebmedia.com/velvetwrcompfaqs.htm

I think it can be done. One of the tips I got from that read, was to put your Social in quarantine and then once you get the Solaris you can add them to the main tank at the same time to better the odds they'll get along long-term. The other thing you got going for you is that the two spp. are different colors, sounds silly, but it plays into compatibility between spp. HTHs