Craigslist question. Please help!?

Okay I want to contact someone on craigslist. They did not leave a phone number or an email address, instead it has that thing underneath the title that says "sale-xxxxx-xxxxxxxxxx@craigslist.org". Of coarse its doesn't actually have "X"s, instead its some kind of code. Now when I click on that, Outlook Express comes up on my computer, and it wants me to configure it and all that junk. I really don't wanna do all that crap, so If I just copy and paste the "sale-xxxxx-xxxxxxxxxx@craigslist.org" into the "to" on Gmail, and then type my message, and send it, will they receive it?