Help with mailmerge

Help!
I left my old company, whereI managed IT just as a new database using Access 2003 was about to be completed. However, the final product is making it difficult to work with mailmerge. It is setup in a way that doesn't allow the use of queries or mailmerge in the standard way.

The designer is adamant that the only way to use mailmerge in a dynamic database is to go to:
1. Insert
2. Field
3. Categories
4. Mailmerge
5. Fieldname

The user then inserts (type in) the fieldname and press ok. This is a very laborious, inflexible process that is not user friendly. Users will need to have prior knowledge of the exact field names before there are able to do this process and we don't have the list readably available to us.

Is there a way to use:
1. Tools
2. Letters and mailings
3. Mailmerge
4. etc

Do let me know what my options are, I feel deeply obligated and desperate to ensure that a project I started deliver its objectives and desired outcomes.