I am experiencing exactly the same issue. I have raised the issue with McAfee support and here is what they have given me:
As per case details we understand that Agent 5.x is not listed in Software manager this is as per product design.
Agent 5.x will not be listed in software manager as there are concerns identified by development and they are still working on this.
You can submit a Product Enhancement Request (P.E.R) and development team will consider the requirement.
KB60021: How to submit a Product Enhancement Request (PER).