Thanks for posting. I may need to see a sample configuration of exactly what you are doing, so that I understand completely. It is my understanding that in your scenario we just need to make sure we do not specify the source address, and we also need to make sure a local route map is in place such that the ping probe is only allowed out the interface to be tested. This route map would prevent the probe ever using or "passing" on the backup link. Please let me know if you are using the route map and still having issues, or I am just misunderstanding the issue entirely. You may also want to respond on this thread with the relevant configuration.