Transaction Code authorization related query --- Not maintain tcode in Role

Dear All,

First of all, I have not found any specific area where I can post my problem.Then I found that the OS level expert should also have expertise in SAP basis administration.My query is as follow;

I have found a scenario where i have seen that a tcode for ex. VA03 is present in an user from SUIM. But when I tried to find out in which Role and profile it is maintained not found.

I have checked each and every Role & Profile but no where it is maintained although the user can run this tcode.

Please note that the tcode VA01 is given as example I actually found this thing for a customized tcode called ZCOA,ZINTROT,ZPROINV etc.

Please help me by giving some idea that how can they maintain this kind of authorization.

Please note that this is a USA company running SAP from 2001 & current SAP version is 4.7.

Thanks,

Suman