Group Policy .adm file

[tester125]

Hello,

I'm creating a .adm file for the first time. I can't find too much help on this issue.
I need to change the desktop "my computer" to the name of the workstation.

Here's the key and value that's currently intact:
Key: [HKEY_CLASSES_ROOT\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}]
Value: LocalizedString:REG_SZC:\WINNT\system32\shell32.dll,-9216@1033,My Computer

I need to change the value to read:
LocalizedStrin:REG_EXPAND_SZ:%Computername%

How could I go about doing this in creating an .ADM file.

Thanks all