[exim] Rewrite question

Hi all,

i'm new to exim and after setting up the following
rewrite rule:

*@*.smtp2 $1@$2 Tbctw

all messages processed by this rule arrive to
destination with "undisclosed-recipient" as "to"
field.
What am i doing wrong?
This rules has to take all address matching "*.smtp2"
and remove ".smtp2" from "to", "cc", "bcc" fields.


Thanks,
Alessandro