Don't forget, you can always convert a field to text just prior to exporting the data.
We have a 401k database that has to be transmitted in text format but I need to manipulate the fields before we send it out. I like to use the Currency data type and General Number format in my tables. Then I change it to text before sending it to Merrill Lynch.
If this doesn't help, give us more feedback.
By the way, your example had commas in it (51,30 or 50,00) even though you said "decimal". Am I missing something here?
Ann