The forum guidelines specifically say not to do this... (append to an old thread, especially when your request is only very loosely related to the original).
The probing can only be done if you are using layout XL and have managed to extract it and bind the instances across to the source schematic (assuming you have one). This is better in IC61X than IC5141 (you didn't say which version you're using - also requested in the guidelines), but even so you probably would need to define the mapping of devices from your source PDK in Configure Physical Hierarchy.
There is further work we are doing right now to get layouts from stream files to become XL compliant, but that's planned for an upcoming release.
You may be better off using Mark Net.
I'm having to guess a bit here because you didn't give much information... (particularly versions, whether you have a schematic, and so on).