CC1121: AFSK modulation in CC11, CC12 or CC13 series

I'm in need to do AFSK over FM.

This means that we do a carrier, then FM modulate onto it the FSK.  For most older devices this was doable by modulating on the PLL loop, but with newer devices its not so easy. 

To make the selection even harder, I need it on VHF (ie 136-170MHz range). 

Does any of the CC11xx, CC12xx or CC13xx devices support this? either out of the box or by a bit of tweaking? Is there any other device I should be looking at that I have missed?

BR

Thomas.