The question is fairly simple but I was not able to find an answer for hours now.
What I need to do is:
RewriteRule ([^#])#(.*) $1\%23$2
Which basically means I want to url escape the freaking hash sign which comes to me from an external codepiece.
backslash (\) does not work to escape this sign... and please don't suggest using %23 instead # because it does not work as well.
(%23 does not match a # because it simply is not == %23)