It would be interesting if it did, given that Celluloid uses Vegas' 24p tools. You may be doing something wrong, but either way, the24p is excellent in Vegas6. Which is why Celluloid uses the Vegas engine.
Celluliod and Ultimate S go through the extra step of rendering all the source files to 24p. This step is unneccessary in Vegas 6 because it can do the 24p final render directly.