Oh, easily.

 

1. Click HTML view.

2. Type: <pre>Line 1<br />Line 2<br />Line 3<br />Line 4</pre>

3. Go back to Normal view.

4. Back to HTML view. Notice how everything is on separate lines now.

5. Back to Normal view. Doublespaced.

 

Edit: I've found a workaround by disabling the HTML view completely and re-implementing it myself using a plain old asp:textbox and some controls to switch between. Clumsy fix disabling part of the program, but it does everything I want it to, and the code I get doesn't have the unwanted line returns.