SRS forward on Exim?

I'm testing libsrs_alt-0.4 using Exiscan ACL 4.42-27 on Exim 4.42.   
However, SRS sender addresses wind up in this format:

SRS0=(secrethash)=(datehash)=(sender domain)=(sender  
local_part)@(recipient domain)

For example, this scenario:

From:  [email protected]
To:    [email protected]

Generates:

From: [email protected]
To:   [email protected]

That means we will not receive any bounce message.  Here is our config:

srsforward_router:
         # Mail that is being sent FROM and TO a non-local address (e.g.  
forward or ASMTP)
         driver = redirect
         domains = !+local_domains
         srs = forward
         condition =  
${lookup{$sender_address_domain}lsearch*{/var/mail/exim/ 
localdomains}{no}{yes}}
         data = $local_part@$domain

Any tips appreciated,

Rich
[email protected]