You could "just" weld or epoxy a M8 (is it?) nut to the place where the captive nut should be...

...or go and buy a captive nut assembly from a hardware store if you're not keen on a visit to the dealer armed with a print out of the picture in the link you posted.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!