After a hours of trying to get my custom HTTProvider working, I reached to a solution.
In the last HTTPProvider tag in VHost.xml file there is :
If we look at the content of RequestFilters tag we see that the provider booking all request filters, so if I put another custom provider below this provider with different RequestFilters it will not work because HTTPServerVersion provider booking all request filters.
To resolve the problem you need to put any new custom provider above HTTPServerVersion in order to take its own request filter, so the order of HTTProviders is important.
I hope that I helped you and I suggest that to change HTTPServerVersion, RequestFilters content to something like *serverinfo...