I downloaded the 6.0 trial version while I was testing out FM10. For me it operated the same as the 5.5's that came with my Filemaker 10. When I read DataDirect's line on v6.0, the changed seemed based on additional security options, as opposed to a bug fix. With a situation as specific as yours, I recommend you go to DataDirect.com, download the trial version, and give those drivers a whirl.
Also, I also searched all over FM's site and found pretty much no information on the ODBC drivers. The place links send you to download ODBC drivers doesn't give you any driver specifics or the ability to download drivers.