Sorry, forgot to mention the pfsense version, it's 1.2-RC4 built on Tue Jan 15 23:05:07 EST 2008
PFS key group, if that's what you mean, has been set to off on the server. I'm not sure how you set PFS on the OS X client, it's somewhat limited in options. Tried setting it to 1,2 and 5 as well, but it seemed to have no effect.