Is there a way to drive the name and/or part number from an equation in a Design Table Excel sheet?

Let's say I have a part named "X.sldprt" with an open-ended configuration publisher allowing me to enter the length when I insert a new part. I want new configurations to be called "X-". Can I enter a column in the Design Table called "Configuration@X.sldprt" (or something similar, perhaps from this list​), such that the new configuration name will be generated from that Excel formula? Alternatively can I use some formula in the Configuration Specific Properties tab to do this?

EDIT: More generally, what is the proper syntax for combining parameters in the Properties menu? And what is the configuration name property called?