Depends on what the problem is...what's the latency between the remote Exchange and your BES server(s)? If it's higher than 35ms, RIM recommends improving on that. In my experience, the value is actually quite a bit higher (I have a couple remote Exchange servers with a few users on one of my BES's and the latency is more like 200ms with no troubles), especially if the pipe is large between the two and not being used to full capacity.
Er, before I ramble too much...what is the problem exactly?
