using Limewire Friends via Facebook on a Mac

[abucka]

Hi.
LimeWire v. 5.2.10
Java v. 1.6.0_11
Windows XP Professional (don't jump on me, I know this is the Mac forum)

When using the LimeWire friends application on LimeWire, I have no trouble logging on to my Facebook account and selecting friends with which to share files. However, my brother, who uses a Mac, can't log on to Facebook via LimeWire Friends. When he tries to log on, the option to do so is not even presented (only the other 3 are). I'm trying to find out how I can share files with him, so is this a universal problem? Or can we share files another way? thanks very much.