According to the Help Center in SAP ByD you cannot change the word Permanent or remove it from core functionality. Type 'work agreement' into the Help Center to see what the official answer is.
I would make sure you are asking the right person in their HR organization. Our only office is in California and we have entered most "regular" employees under the work agreement type "Permanent."
There is a distinction between calling someone permanent or regular from an HR liability standpoint and using an un-editable field in a packaged application like SAP. There is no other option for the HR organization to use in this case. Is it there intent to make someone "permanent" by choosing that field? No.
We have some nutty laws here in California like distinguishing between "permanent" vs. "regular" or "full-time." I just roll my eyes when I hear stuff like this.
Jim