Under the \xxWIN subdirectory, create a subdirectory called CustRP and place your custom .RPT's there. If you only want users of a particular Group to have access to the report, then create another directory below CustRP using the group ID and place the RPT there. Use the RPT Properties to name the report (or the program will default to the RPT name itself if the field is blank).

This feature is only available in version 6.8B and above products (so hasn't yet made it to Receivables, Invoices or Time&Billing).

Does this help?

Just to follow up on Andrew's post, if you need more detailed information about setting up the report menu and security levels for Custom Reports, the information can be found on page 4-7 of the Adagio Fundamentals manual (second edition).