Set up a free account on MailChimp. Use their drag and drop visual editor. Click the "HTML" tab and copy the code. Paste it into Interspire. Remove any MailChimp-specific code.

I use Aweber.
Don't stop taking massive action.
Best of Luck,
Michael T. Irvin
michaelirvin.net
My books are available exclusively through Amazon Books. Check out my book "Copywriting Blackbook of Secrets"
Copywriting, Startups, Internet Entrepreneur, Online Marketing, Making Money

Have a look at http://edmdesigner.com/
I have not personally tried it.