Of course! You can do this in the Text Editor and in the Full-featured HTML Editor. Using the Text Editor will render your HTML more accurately and is the least problematic of the two options.

Paste your HTML into the Text Editor (recommended method):

1. First set your Default Editor to Text Editor. Go to Lists, and click on List Settings.
2. In the Default Editor field towards the bottom of the page, select "Text Editor" and click the Update List Settings button.
3. When you create a new message, you can paste your HTML into the Message field. When the Editor is set to Text, the Message field is absolutely bare, and your HTML will be preserved exactly as you paste it.
4. To preview your HTML message, click Save Changes and Preview.
   

The reason for using the Text Editor when you have a ready-to-use HTML message is that the Full-featured HTML Editor will insert some HTML tags that may conflict with your HTML and compromise the email message's final appearance.

Paste your HTML into the Full-featured HTML Editor:

1. Make sure you’ve chosen Full-featured HTML editor as your Default Editor in List Settings.
2. When you create a new message, click the little HTML link in the WYSIWYG interface (it’s just under the format drop down menus). Paste your HTML into the HTML source editor screen that appears. You can paste over the HTML that appears in the screen.
3. To preview your HTML message, click Save Changes and Preview.
   

The HTML editor is designed to create HTML emails with a user-friendly interface within the application—it is not for editing ready-made HTML code. Since bringing outside HTML into an HTML editor can be problematic, keep in mind these caveats when pasting your HTML into the WYSIWYG:

• When creating your own HTML, use the 4.01 transitional standard. This standard is compatible with the WYSIWYG featured in Mustang List. While there may still be a few problems with the way the WYSIWYG digests your HTML coding, this will help a lot.
• Carefully test the HTML in your email client and in different webmail accounts to ensure that are no problems brought up by the HTML import/pasting process. You want to make sure everything looks good and renders properly.
• Once you’ve finalized an email message after careful testing, it would be best if you used the finalized version as a template for future messages. Clone the perfected version and replace the text and images from within the WYSIWYG.
• Even if you give your designers the HTML that was tweaked and finalized in Mustang List to use when they create new HTML email messages, tags can be automatically added and changes can occur during the import/paste process into their HTML editor and then again into Mustang List that will require you to retest everything (hence our recommendation above).
  

If there are problems you cannot resolve, contact Mustang List. Mustang List can create custom templates and will do this testing for you. Once the template is finalized, you can create future messages with the template by accessing it in the Mustang List templates when you add a new message.