Hi again,
Unfortunately, this is one of the problems of using InfoPath's built-in SQL functionality. It limits you to the datatypes that map to SQL. After you have created the form, it won't go out and try to determine the data types again. You have to recreate the form from the SQL database. But, even then, the datatypes don't match up perfectly (for example, you can't have rich text nodes or images without writing code). This isn't the only limitation with InfoPath's default SQL data connection. In fact, there are many. When you need to change your form or database, it is very painful because you essentially have to recreate your form every time something changes. You can't just add a new node to your main data source.
Reading back in this post, it seems like there are two distinct issues - the issue that you and travisBickle have is related to the hard-binding between your database and the InfoPath form. You really have only one good option here and that's what travisBickle mentioned:
Use a Web service in between SQL and your InfoPath form. If you don't have time to "age 10 years" as travisBickle mentioned, we have developed a Web service suite already that you can use to quickly solve your problem. Download the free dev edition here. You will have to create your form again using an true XML schema - just start InfoPath, choose Design a Form Template and select a Blank form. Click on Data Source, select myFields, and add the fields and groups based on your form's needs. Open your old form and click in the view. Press ctrl-a to select all controls and then ctrl-c to copy them to the clipboard. Switch to your new form. Click on the view and press ctrl-v to paste the view into this new form. Next, go around to all of the fields, right clicking and changing binding. That should take about 30 minutes or so but depends on how big your view is. After that laborious re-bind you will never have to re-design your form again and you will be able to change the binding of any and all fields to point at whatever node and data types you want. Publish the new form to your database using the DBXL Admin Tool (see the Getting Started notes). Add a submit data connection to the form (See Getting Started again). After you have confirmed that the data is submitting correctly to your database you can create a mapping for your document type (ala XSN). In DBXL Admin Tool just click on Edit, add the datasource string, save and switch to the Mapping tab. This is all described in a document on how to do mapping. Anyway, since your mapping is independent of the submit, changes to your form or database won't affect the submit process and you can add nodes to your form whenver you want. This gives you the freedom you need. Compare to the direct-mapping of the built in SQL connection and you will save countless hours and headaches down the road.
Good luck!