As of this writing, the current version of Pegasus (v4.12a) has a very small buffer for data. The preferred method for replying with Pegasus is to disable "Quote the Original Message" and use the clipboard option:

1. Download PPTweaker
2. In PPTweaker, select the "Reply" tab
3. Change the "Preset" to "Custom"
4. Uncheck the Field "Quote the original Message"
5. Check the Field "Copy the original message to the clipboard"
6. See this screenshot to verify all other settings
7. Press Save

When you reply, you can "paste" the contents of the clipboard into the message.