It has always bedeviled me how to submit an ATG form using a text link. I have asked many people about this but no one seems to know. Finally with the help of ATG support I figured it out.
Below is a simple example of how to do it. The trick is the hidden submit input which triggers ATG to call the handleSubmit method of the form handler.
<%@ taglib uri="/dspTaglib" prefix="dsp"%>