getting rc =9 from ssoext.SetProperty

Using the SAPSSOEXT example I'm trying to set up the logging file by using:

inttrc=  ssoext.SetProperty("SAP_EXT_TRC", "C:\\Users...");

inttrl=ssoext.SetProperty("SAP_EXT_TRL", "3");

each one just returns a 9 and the file never appears to be created, or if I pre-make the file it still doesn't have anything written to it.

I assumed it was this straight forward, am I missing something here?