External Autoresponder

[Bellemom]

At the moment my site is hosted elsewhere. But, I am so enthralled with the possibilities that BV offers with their website design that I have spent the past couple of days rebuilding my site entirely (with a lot of fun I may add) whereas my old site is impossible for me to understend (it was built by someone else). I intend to host my site (and the others I already have a domain name for) with BV but need to know if I can use the external autorespnder I am using right now for my newsletter. How can I "attach" it to my form which I have created on my index page on the soon to be published site here with BV?
(sorry, a long question for a simple one)