Here's one way to adapt it to work with campaign while keeping the weapon rank restrictions from the vanilla campaign:
http://modulaatio.com/runningwithrifles ... r_sale.zipThat's a full overlay package and it includes the files from Xaoc Groza's overlay, usable in both quick match and campaign.
Seems the scripts used by the campaign don't like whitespace in internal folder names, hence the rename to rares_for_sale.
Installation instructions are basically same as in the original post, just rares_for_sale for folder name.
What I added was
* rares_for_sale\overlay_config.xml, defining which file to use to start the campaign
* rares_for_sale\scripts\start_invasion.php, script to specialize some vanilla campaign components in order to 1) remove vanilla campaign faction specific resource changes over quick matches and 2) clear rare weapon declarations (in_stock=0) from vanilla campaign weapons
Use "Setup custom campaign" button in "Start new campaign", enable the mod and start the campaign.
Feel free to integrate these back to the original package if need be.