[ozzy47]

What you could do is create a new plugin.

1. Log into the ACP.
2. On the side menu expand "Products & Plugins"
3. Click on "Plugin Manager"
4. At the very bottom there is a link to "Add New Plugin"
5. On that page put in the following information-
   
   Product: vBulletin (this should be default)
   Title: Replace Minutes In Postbit
   Hook: postbit_display_complete (from a drop-down list)
   Execution Order: 5 (default value)

$vbulletin->templatecache['postbit_legacy'] = str_replace('Minutes','Mins',$vbulletin->templatecache['postbit_legacy']);

I tested this with the word Minutes directly in the postbit, and it works, I did not test it with this mod, but it should work.