[Exim] multiple pipes in aliases file

Hi. I'm wondering what the trick is to get multiple pipes to work in
the aliases file. The entry I"m trying (and the one that works in
sendmail) is:

kxt: "|/opt/local/bin/stripmime|/home/mailman/mail/wrapper post kxt"

I've tried adding a space before the second pipe, but that didn't help.

In the above entry, it seems exim takes
"/opt/local/bin/stripmime|/home/mailman/mail/wrapper" as the program to
pipe to, while if I try it as:

kxt: "|/opt/local/bin/stripmime |/home/mailman/mail/wrapper post kxt"
or
kxt: "|/opt/local/bin/stripmime |'/home/mailman/mail/wrapper post kxt'"

it calls stripmime with three arguments: /home/mailman/mail/wrapper,
post, and kxt, which of course fails.

What's the magic syntax? Thanks...