I don't think you still need Composer to package the agent.

First, create a simple script like this,

!/bin/bash

Change the ProxySG with the Client Manager URL

defaults write com.bluecoat.ua cmurl https://<ProxySG>:8084

Then, Just download the dmg file from the Client Manager or BlueCoat website, Mount the dmg file, drag the .pkg file to your Casper Admin and the script you made and save.

Create the policy, Trigger at Login or Check-In, Frequency - One Per Computer, add the package, then add the script (make sure to select "Before" on the priority because the script needs to run before the install of the agent happens) then scope it to all machines need filtering.

Eigger- thank you, I will give this a go when I get to the office this morning. Really appreciate the response, perhaps my flaw was not including a script such as this. I will report back what I find after testing.

As a followup Eigger - I'm being told that:

"Change the ProxySG with the Client Manager URL

defaults write com.bluecoat.ua cmurl https://<ProxySG>:8084"

is only for an on prem server. We are not hosting a Bluecoat instance on prem and thus do not have a Client Manager URL.
So back to the drawing board for me. I am going to try bypassing Composer completely and just using the .pkg direct from bluecoat and uploading via Casper Admin.

As a general rule, if you can get a .pkg directly from the vendor, there's no need to use Composer - you can just upload the .pkg to the server via Casper Admin and you're done (after you create the policy in JSS). However there are, on occasion, some installers that require a script to be run along side the pkg. Some notable examples for us are Pulse Secure and Netskope. For those, I have to put the installer pkg and the script in a folder in /Users/Shared/ and then put that folder into Composer. Luckily those kinds of situations are far and few between.

We also have BlueCoat and I put the pkg installer in Casper Admin as described above. The defaults write com.bluecoat.ua cmurl https://<ProxySG>:8084 part was just added as a command to run in the policy for the installer because we do have an on-premises server . if you don't have an on-premises server, then i'm pretty sure that's a non-issue for you.

EDIT I should have said that some installers require a script AND/OR a configuration file to be run along side or referenced.

Update - Adding the extracted Bluecoat .pkg file from Bluecoat DMG to Casper Admin and then deploying via Policy/Casper Remote worked. Thank you both so much. Much easier than I was thinking it was going to be. Apparently I either confused myself profusely or our JumpStart trainer didn't explain this very well. I was under the impression that Most everything(.pkg files included) had to be repackaged via composer first.