You have to
1. Go to your PROFILE control panel located all the way up under where it says "The Growing Hit 317 Rs Private Server RapeScap3" you should see it in between USERGROUPS and MESSAGES/NO MESSAGES.
2. Click on the preferences tab.
3. Find and check the option that says "always attach signature".
4. Go to the last message you posted click "edit" and under the message there should be a bar called "options" with an arrow pointing down at the far right.
5. Click the arrow and it will give you a list of options
6. Find and check "Attach signature", and it will remember you preferences, and always attach your signature.
I got this from Genocide Post! Credits all go to Genocide for the guide