Mount sitting animation

Right now I having a great deal of difficulty trying to get my player to sit in the right posses when mounted to a vehicle. I have seat up my player so that the arms holding the gun move up and down with the blend. Just like the Ork has but with my animation for sitting blends with the arms and does not set the arms in the right location ( hands on the stirring wheel or holding on to support bar.)

I have searched the forums for help and cam up empty handed.. and the doc's don't help out.