The E1 Tool script is intended to allow linux users to make full use of the Creative Technology Ltd Sound Blaster E1. It currently allows switching the secondary port between input and output mode.
Currenltly the script has 2 commands:
sudo e1tool.sh -e
Puts the second port into microphone mode, disabling the internal microphone.
sudo e1tool.sh -i
Puts the second port back into headphones mode. This also re-enables the internal microphone of the SoundBlaster E1.
This soultion was discovered by user ids1024 on the Arch Linux forums. The thread is here.