These directions will remap your F1 key in LT2006 or higher to act like theescape key: same concept should work for other F-keys too:
1. Right-click on a toolbar and select Customize... to open the CUI Editor.
2. In the upper left area, expand Keyboard Shortcuts and then Shortcut Keys.
3. Drag a command from the command list below into the Shortcut Keys (I used the first command .XY).
4. The command should now be in the Shortcut Keys area. This creates a new shortcut key with the same name as the command. Right-click on the new shortcut key and select Rename. Rename it to "F1 Remap" (no quotes).
5. In the properties area for the new shortcut key, Change the description to something else (or just delete the text there).
6. Change the macro to the following, which basically cancels any running command, you can add another command if you desire: ^C^C
7. In the Keys text area of the access heading, clickinside the text area to activate it and then press the button on the right with the three dots.
8. The shortcut keys dialogue box comes up. Place a cursor in the area called "Press new shortcut key:" and press the F1 Key on your keyboard. F1 should now appear in that box. Click on the Assign button. F1 should now appear in the Current Keys section. Click on OK.
9. Click on Apply in the CUI editor and then OK.
If you have LT2005 or lower, click HERE.