Override HTTP-Method

Hello,

is it possible to override the $request_method?
I have the problem that a well known client tries to place a request with method "0". This has its roots in a bug that would take long time to fix.
Is it possible to do something like

if ($request_method = 0){
set $request_method POST;
}

I did a quick try on this but i qot an error that the variable "$request_method" is duplicate.

Kind Regards,

Benjamin