I can suggest like this configuration. It's difficult to rate limit and to not drop marked packets. But what you can do is observe the traffic patterns of your DSCP marked packets and know how much avg bandwidth it needs.
class-map match-all test
match ip dscp 46
class-map match-any test-1
policy-map aaa
class test
priority xxx
class test-1
police xxxxx xxx
Refer to this document for more information...
http://www.cisco.com/warp/public/473/134.html