Unfortunately, no. Our system has been specifically built not to support attachments. We did this for a number of reasons.
- We ensure that your campaigns are unable to send viruses that propagate through attachments.
- You're not forcing an attachment down every recipients throat. Large attachments + slow connection = angry subscriber.
If you have a file that you'd like to give to your customers, we recommend that you host the file on your own server and then place a link to the file within your email. This also means you won't clog your subscriber's inbox with attachments they may not even use.
Here's a quick example of how you might promote a PDF document in their email instead of actually attaching it.

Alternately, you can consider using a file hosting service like Digioh, which provides a share URL that you can use to link to the file from your campaign.