Mail Merge Query - Format of Merge Fields in Word

Another mail merge query!

Does anybody know the formatting syntax / code to edit the merged data within a word doc from excel? For instance, when I perform a merge with figures containing thousands, how to I show a ',' in the resultant field in Word?

I know that to format data in a way to limit the number of decimal places is to insert '\#0.00' after the merge field string - do I need to insert a comma in there somewhere?!?

This is driving me nuts! Argh!