sipp

The [routes]-field reuses the Record-Route of the message received before
(where the rss-attribute is true).

In SIPp 1.x, this is done correctly:

Received message:
-----------------------
SIP/2.0 200 OK
Via: SIP/2.0/UDP xx.xx.xx.x:5060;branch=z9hG4bK-21289-1-5
To: bob <sip:bob@somewhere.net>;tag=1
From: alice <sip:alice@somewhere.net>;tag=1
...
Record-Route: <sip:aa@12.14.16.18:5060;transport=UDP;lr>
...
-----------------------

Sent message (using [routes])
-----------------------
ACK sip:aaa@12.14.16.20:5060 SIP/2.0
Via: SIP/2.0/UDP xx.xx.xx.x:5060;branch=z9hG4bK-21289-1-5
To: bob <sip:bob@somewhere.net>;tag=1
From: alice <sip:alice@somewhere.net>;tag=1
...
Route: <sip:aa@12.14.16.18:5060;transport=UDP;lr>
...
-----------------------

In SIPp 2.0 (the same xml-scneario), there is a colon too much:
-----------------------
ACK aaa@12.14.16.20:5060 SIP/2.0
Via: SIP/2.0/UDP xx.xx.xx.x:5060;branch=z9hG4bK-20650-1-5
To: bob <sip:bob@somewhere.net>;tag=1
From: alice <sip:alice@somewhere.net>;tag=1
...
Route: : <sip:aa@12.14.16.18:5060;transport=UDP;lr>
...
-----------------------