Try using a technique known as an unbound form. The data entry fields on the form are stored as local variables. When the user selects the "save" option, then establish your RecordSet in Add Mode and move the variables into the corresponding fields.
This is a tried and tested method of "remote data entry" and works with front-ends for middle-ware to main frames, web-based applications, and any other form of client/server data entry.
What you are currently trying is known as a "bound-form". You are trying to enter data directly into the RecordSet fields. This is a good technique; however, you are limited by the way the Data Control you are using functions. Using the local variables and th unbound technique gives you more control of the situation. You do have to write a little more code when using this technique; however, then benefits, in your situation, are worth it.