[Dovecot] sieve-filter ignoring separator

It seems like running sieve-filter from the console ignores the separator setting, thus not letting me filter into folder names containing dots.

Normal delivery using lda handles it just fine, but not when using the sieve-filter command.

Character not allowed in mailbox name: '.'

Is there anyway to override this or is patching and recompiling the source my only option?

# dovecot --version 2.1.9

/Isak