Programmatic form capture

I am trying to use programmatic as described at http://help.clickdimensions.com/programmatic-form-capture/ to create leads on our site.

I am using my own form in order to automate the form capture, and I have put the tracking script after the closing form tag and before the closing body tag as described.

I would normally use JavaScript to submit the form, but in an initial test I submitted it manually by clicking the submit button.

I found that a lead was generated by the submission of the form, and a visit was generated by the tracking code.

But the "lead" field in the visit was blank, but the "anonymous visitor" field was filled with the name of the IP Organization.

Is there anything I could have missed out from the form to prevent the lead being added to the visit?

Thanks.