Use $ in secure variable value

I'm trying to use a $ sign in a secure variable, but it does not get copied into the build. Using a command like xcopy "d:\myfolder\" "\\ext-server\e$\newfolder\" but instead it shows up in the build script like xcopy "d:\myfolder\" "\\ext-server\e\newfolder\" which of course makes it fail the copy action. Is there any way around this?