Mita,
You should be able to do this when creating the junction by using the ‘-v’ option to specify the host header which is to be sent to the junctioned server, and the ‘-I’ option to specify the Host header which is received from the client. This does however mean that either host header could be supplied to WebSEAL to match the virtual host junction. For further information refer to the documentation:
https://www.ibm.com/docs/en/sva/11.0.1?topic=hosting-creation-virtual-host-junction.
I hope that this helps.
Scott.