Customizing menu items

I need to change the Item description in menus, related to PO Orders, Deliveries, Invoices (generally on several standard documents of the Purchasing and Sales area).

Looking at some answers already given, I saw a suggestion to go through:

Administration->System Inizialization->Document Numbering

and then insert a different description in the column "Change Menu Names".

This is true and great but only if you don't have selected "Permit More than One Document Type per Series" on the:

Administration->System Inizialization->Company details

Is there any other way to obtain the same result?

My environment is SBO 2007A SP01 PL08.

Thanks

Antonio