open the max script reference and search for unwrap_uvw it should be in there somewhere. you might want to look at textools. i think this is covered allready. its definately in chuggnuts uv tools. both are excellent downloads
If you open the maxscript listener f11, go to macrorecorder and enable it you will see script output every time you do something in max. If you surround this in the macroscript name category:"category" tooltip:"description" ( ) you can automate things really easily and add pretty much anything to a hotkey