I have a PDF form that I need to convert to a Word Mail Merge, and my original plan was to add the image into the background, and add a table to the Word documet to add the merge fields into separate cells to match the form. My intention was to lock the table except for the cells where the data was to be entered, and protect the document, but I have found that I cannot use mail merge and protected documents together. This means that the end user is not prevented from adjusting the table, or typing into cells which are not part of the editable field list. I need to keep the data entry areas locked to match the existing form (this cannot be allowed to be altered!)

Is there any way to prevent the end user from editing the document, while allowing them to add/change the data/merge fields in the areas that I need to specify?