The second half of the contact toast doesn't support colours, it's meant for using the contact name, then info about them in the second bit, and the info wouldn't need colours.
But you could just use:
code:
MsgPlus.DisplayToastContact('Contact Counter', '·$3Contacts online: '+online+'.$0'+'·$4contacts offline : '+offline+'·$0','', '' , '', '');
It'd probably wrap over, though I haven't tested. Also, why not use the nice, easier colour codes...