I got an answer from over at StackOverflow …
http://stackoverflow.com/questions/269725/biztalk-msmq-userid-and-password-in-a-bindings-file#270409
from David Hall …
What you are looking for in your binding file is the
<TransportTypeData> element of your MSMQ send port. This contains
all of your adapter config information as encoded data.
Within that element there is a userName and password section. The
password will be masked out with asterisks. Put the password for the
environment there and import the binding.
The part of the encoded data with username and password will look something like below:
&lt;userName&gt;YourUserName&lt;/userName&
amp;gt;&lt;password&gt;**&lt;/password&gt;