I don't think you can it is a pre-defined key.
Create accelerator keys (keyboard shortcuts) for commands
Published date: 2003-03-19
ID: TS22496
Applies to:
AutoCAD® 2004
AutoCAD® 2002
AutoCAD® 2000i
AutoCAD® 2000
AutoCAD LT® 2004
AutoCAD LT® 2002
AutoCAD LT® 2000i
AutoCAD LT® 2000
Issue
You want to create keyboard shortcuts, or accelerator keys, for commands that you use frequently.
Solution
Important: Some keys cannot be modified. Refer to the Customization Guide for a list of keys that are already defined. Do not modify predefined keys.
You can use one of the following methods to create accelerator keys in the MNU file:
Use the Customize dialog box (Keyboard tab)
Manually add the keys to the MNU file
Method #1: Use Customize dialog box
Right-click any toolbar button and click Customize on the shortcut menu.
In the Customize dialog box, click the Keyboard tab.
Select a command.
Place the insertion point in the Press New Shortcut Key text box.
Press the key combination that you want to assign to the command.
If an accelerator key already exists for that command, it will appear in the Current Keys box. If the key combination you specify is already assigned to a different command, the command will appear in the Currently Assigned To box.
To see a list of all current accelerator keys, click Show All.
Click Assign, and then close the Customize dialog box to recompile the menu.
Method #2: Manually add accelerators keys to MNU file
In a text editor, such as Microsoft® Notepad, open the menu template file from the Support folder.
Locate the section labeled ***ACCELERATORS.
At the end of the ***ACCELERATORS section, use one of the following formats to add a new accelerator key:
[<Key Sequence>]^C^C<Command Name>
- or -
ID_<Command Name> [<Key Sequence>]
An example of these formats is shown below. The first one assigns the CTRL+Q key combination to invoke the QUIT command; the second one assigns the SHIFT+CTRL+L key combination to invoke the LINE command.
[CONTROL+"Q"]^C^C_quit
ID_Line [SHIFT+CONTROL+"L"]
Save the MNU file to the Support folder, replacing the existing MNU file.
Now, you must activate the new accelrator keys.
To activate new accelerators keys
Start your Autodesk software.
Enter menu on the command line.
In the Select Menu File dialog box, browse to the Support folder.
From the File Type list, select MNU as the file type.
Select the MNU file that includes the accelerator keys and click Open.
Click Yes to continue loading the MNU file.
This process recompiles the menu so you can use the new accelerator keys.