I don't know for sure, but there might not be any further command line parameters for that program.
But there is a zip library for Basic4PPC , since I couldn't find it via search, I'll attach a sample project that should have everything necessary to either add the extract feature directly in your program or create a seperate command line utility to extract zip files with Shell. I did not make that library.
I don't have everything installed that's required to compile anymore, so it's untested.
Alternatively you could look for zip programs for windows mobile, which have documentation of the command line parameters.