Hmmm, maybe try a hot oil treatment or something? Like the pantene 3 minute miracle? If it's frizzy because it's unhealthy then you can't do anything but make it healthy again.
Personally I would condition it generously.
They also make special combs, you flip the mane over to the other side and razor the top, which then becomes the bottom that you would have pulled when you flip it back over. Does that make sense?
This is it http://www.saddlerywarehouse.co.nz/afawcs0126509/CATID=8/SUBID=72/ID=16482/SID=314739621/productdetails.html
Apart from that probably the only thing you could do would be to cut it, it will look out of place in general, but once its plaited up it looks fine.