verifymsg: How to pass log message (check-in comments)?

I want to verify whether the check-in comments are not null or are in
a certain format. I had figured out that verifymsg does the thing for
me. I had written a script that will do the necessary checks, but some
how I cant get the log message (check-in comments) passed to the
script.

The entry in the verifymsg looks like this:
testcvsmodule/* perl -S verify.pl %l %p %r ${USER}

I tried various version of it ..
testcvsmodule/* perl -S verify.pl
testcvsmodule/* perl -S verify.pl %1
testcvsmodule/* perl -S verify.pl %l %p %r ${USER}
testcvsmodule/* perl -S verify.pl ${l} ${USER}
testcvsmodule/* perl -S verify.pl %{$sV}

But unable to pass the required parameter.

May be I am missing something very simple.
Any help would be appreciated.
Thanks
Amol.