reftex-citation doesn't ask for pages

[Sven Bretfeld]

Hello

I have a little problem here. Possibly I have misunderstood
something. I've made my own citation-format to make reftex work
together with biblatex:

(setq reftex-cite-format
  '((?\C-m . "\\cite[]{%l}")
   (?t    . "\\textcite[]{%l}")
   (?p    . "\\parencite[]{%l}")
   (?o    . "\\citepr[]{%l}")
   (?n    . "\\nocite{%l}")))
(setq reftex-cite-prompt-optional-args t)

I was thinking the last line makes reftex ask for the page number
after hitting C-c [, but it doesn't work. After asking me for the
cite-key, reftex inserts the cite-command with empty [], so that I
have to jump back to insert the page number manually. It's the same
when I define the cite-format with two pairs of braces.

What have I done wrong?

Thanks for help
Sven