Pues lo cierto es que no me entero de como hacerlo... Yo se de modificar ficheros hexadecimales y todo lo que haga falta... pero esque no me entero...

Lo mas claro que he encontrado es lo siguiente:
How to Replace Menu items in Popup Menu with Other Applications

It is quite obvious that you may have applications other than those included in Popup Menu and you may want to change the shortcuts in PopupMenu::

Open zsbpopupmenu in Hex Editor (You can use X-Plore's Hex Viewer Option) ::

here we will take the example of "CALL" option availabe under "NEW" submenu :

1. Goto the menu item "CALL" (it is at the very begining of file)

2. you will see the the code 70 09 near to the text "CALL"

3. This 70 09 is the identifier of the Menu Item "CALL"

4. similarly you will find the Identifier of other menu items in the form of XX 09

5. Now replace the Text "CALL" with something you want (maximum 15 chars) for example "X-Plore"


[*This is applicable for my version of popup menu]

6. Now search the file for another instance of 70 09

7. there you will find like 70 09 00 00 F1 51 00 10

8. This F1 51 00 10 is the UID of "CALL" application. Now You have to replace this UID with the UID of your application in reverse order.

Suppose we want to use X-Plore. The UID of X-Plore is 0xA0000BCD so we will replace 70 09 00 00 F1 51 00 10 to 70 09 00 00 CD 0B 00 A0

Now our menu item "Call" is replaced to "X-Plore"

You can use Swiss Manager Pro to get the information of UID for a particular application
By GaPaTa

No lo termino de ver muy claro... ¿Alguien lo ha conseguido?