Hi Shaun,
No its not possible to add html forms to a page using the editor. There is a limitation to one html form per page in ASP.NET and that form already exists so adding another one will likely cause errors on your page and will not work.
I'm almost finished with my new Form Wizard which will be a for sale feature hopefully on sale by the end of next week. It allows easily creating arbitrary forms to capture any data you want, but it does not post to external sites.
If you need to post to an external site about all I can suggest is create a simple html page with the form and then load it inside an iframe. It might work.
Hope it helps,
Joe