I have seen a messages it was responded by Nitass who said that " i have not found command to silently drop CCA message." this mean this irule could not drop result code 5012 .if you do not mind to drop or reject tcp connection (not a message), you can use drop or reject command.
Also I can upgrade the device from v10 to v11.I have seen another irule was written as V11.I can upgrade software to V11 if you tested before. v11 has introduced a number of new DIAMETER:: commands. it would be great if you can upgrade to v11.
let us know if there is any problem. cheer!