That router configuration looks good to me, but just make sure that the WSA was configured for Transparent mode during the initial System Setup Wizard configuration. If it was initially configured for explicit only, then you will need to run the wizard again to change it to transparent.
Also, make sure to add a deny statement to the top of access-list 110 for the WSA IP address if the WSA will be going out to the Internet through the same e0/1 interface. Loops are bad. :twisted:
Cheers,
Jason