These tiny screws do get lost sometimes and replacement costs for two tiny screws are not cheap (costs range from $10-$20 depending on shipping location). Fortunately, if you are a DIY type of person, you can modify some screws from your local hardware store to make new ones. I'm sure you were hoping that the local hardware store would sell the exact size you need but unfortunately they don't. It's just not a commonly used size screw.
To create your own replacement screws to hold up the adjuster cover, follow these steps:
1. Buy two M6x1.00 phillips screws (preferably flat head but round will do) from your local hardware store like Ace Hardware, Lowe's, Home Depot, etc...
2. Grind or cut screws to 5.5mm, no longer than 5.6mm from the pan head. This can be done by yourself and if you don't know how you can get your local mechanic or machine shop to do it for you.
Hopefully this helps : )