Hello,
There are few Simple Steps.
1) Install SPC on the server.
2) Create the Custom packages from SPC
Deploying clients by using Custom Installation
After finishing the creation of the installation package, open the folder where the package was created.
Inside the folder, copy the SyLink.xml file. This File is something we could require for SylinkReplacer.
3) Run the SylinkReplacer
https://www-secure.symantec.com/connect/downloads/sylinkreplacer-tool-connecting-sep-clients-sepm
By Sylink Replacing, you would be able to get those clients communicate to the SPC back.
That would resolve your Issue.