使用参数从Delphi调用SQL Server存储过程？

I'm trying to call SP_SPACEUSED from Delphi 2010 using ADO. I can call it without arguments by using TSQLStoredProc, and setting the StoredProcName. This gives me the database size. I now need a specific table size, and SP_SPACEUSED takes a single arugument, @objname. How do I pass this as an argument. I have tried passing this as a parameter, but this doesn't work. Is it a parameter? Can I do this from Delphi?I'm trying to call SP_SPACEUSED from Delphi 201