You have to reconfigure the SSA to allow legacy connections if you requir TCP for deployment.
the command I believe is csamconfigedit port=4105 delete
However, I also strongly discourage this, even in enviroments that require TCP only. This was a nightmare, but this was even more of a nightmare dealing with tcp only agents upgrading from 11.x to 12.5. The reason I say this is because they require the legacy method to talk to SS, DM and etc. Also note that everytime you upgrade, modify, or repair the 12.5 agent, the csampmux goes back to default settings essentially turning this back on... I have yet to figure out the gobalconfig that it spoke of and where it actually saves this data. I bet Rich will be able to shed some light on this.
Once you do it on a DM, you will want it on the SS, and then you are going to want it on all Agents. Very hard to manage and control properly. I would strongly encourage leaving the default setting with everything running UDP. If you look at the port configuration with 4104 (udp) (csamconfigedit port=4104 display) you will notice that this is basically doing a legacy mode already, which is why cam has no problem with it :)
I also think when you mess around with this type of setting, you may run in to boot Server issues. I have seen this in a few different enviroments.
You may even run into issues with TCP only when the path portion of the cam.cfg is setup properly.