UDK Modeling questions Thread

This is the remake of the green soldier model im working on for the Unreal Development Kit (UDK), and im having concerns of the bone structure. I used the UT3 Male Sample model's bones but am i able to tweak the skeleton to fit my model like the original model (for source) had his arms straightened out but the bones and sample mesh had this pose instead. I really want to have the character use the default UDK character animations w/o having to make a new model. Any help on this would be VERY appreciated.

thanks