Hi, does anybody know how to sinc Sibelius 5 (in a Mac) and midioverlan?

I'm trying to connect my Mac with my pc. The connections works because I see activity in the MolCp Midi monitor on both computers. The weird thing is that my Sibelius 4 on the PC does recognize MOL but my Sibelius 5 on the Mac Don't. Any idea about this? I appreciate any help.