I use Halion a lot, and it seems to be built from the gound up to integrate into a host application...no so Gigastudio.
The only way to get it to work is with "real time export" export enabled. But the main reason I use a common machine is to be able to do off line processing. I have a number of otehr problems too, I get random pitch changes with Rewired tracks, not to mention the delay caused by SX showing 8 x 16 midi ports for GS when used in Rewire mode.
Shame, I like the way Rewired tracks show up in my mixer. Seems to be a consensus too around here that the wrapper by FX Max is more efficient, and just plain works better.
Any words of wisdom before I spend more money on the wrapper??