To assign a shortcut (accelerator) to a command, add an ampersand (&) in the title of the tool, just before the letter that you want to use as the access key.
After the ampersand has been added the accelerator needs to be included as a keyboard shortcut.
On the Tools menu, click Options
Select Keyboard on the Environment page
In the Show commands containing list, type Tools
In the Command names list, locate the appropriate External Command n entry
Put the cursor in the Press shortcut keys box, and then press the keys you want to assign to the external tool
Click Assign