Help with SQL 2005 sp_helpsrvrolemember

I was wondering why I would get different results using sp_helpsrvrolemember, depending upon what account is logged in.  We used sp_helpsrvrolemember in 2000 for monitoring role changes.  In 2000 we ran the procedure under a simple login (no server roles) and the results were accurate.  With 2005 running the procedure under a "simple login", results only in the retun of the SA  account (which happens to be disabled) nothing else.  If I run the procedure under a sysadmin account the results are accurate.   I really do not want to make the account a sysadmin or anything higher than it was on SQL 2000, does anyone have an idea where the problem may lie or a work around without elevating rights?

Thank you in advance