Done some research, and a way to do this is to use "match protocol" option to include udp.
But unfortuneately "match protocol" does not appear to be an option in my IOS. Here are my only choices when I get this far...
rtr-1# set security nat destination rule-set inbound rule newserver-nat match ? Possible completions: + apply-groups Groups from which to inherit configuration data + apply-groups-except Don't inherit configuration data from these groups > destination-address Destination address > destination-port Destination port + source-address Source address 
So apparantly I don't have an option to match against a udp port??
Is there another way to do port forwarding on udp ports?
Otherwise do I have to upgrade my IOS (10.R3.10) to a later version that supports "match protocol"? (I hope not)