Using Sage CRM 7.3 SP3 integrated with Sage 100 2016

I have written a .net customization that reads a data file, creates a communication record, and attaches a pdf file to the communication. We have found that on occasion the wrong communication ID value may exist in the data file. I have tried to add a tab to the communication record that would allow the user to see the linked attachments and to remove/add attachments to correct issues.

When I add a tab to the communication tab group, it seems to have no effect. I also looked at adding a button group to the communication but that doesn't seem to work either. I'm trying to determine if managing the attachments to a communication is possible.

Thanks,
John