re-builder vs replace-regexp

[Андрей Парамонов]

Re-Builder is a great tool. It allows interactive search with
incredibly handy highlight, subexpression mode, etc. However, one
often needs not just search by regexp, but also perform regexp
replace. I thought reb-copy command would help me to pass my regexp to
replace-regexp. But replace-regexp doesn't understand the result of
reb-copy, i.e. for default *scratch* buffer the following regexp works
in Re-Builder:

"\\(file\\)"

but to make it suitable for search-forward-regexp/replace-regexp I
need to manually adjust it to

\(file\)

I find it really inconvenient (the larger regexp the more
inconvenient). Should I report a bug, or I'm missing something basic?
I'm running GNU Emacs 23.3.1.

Best wishes,
Andrey Paramonov