You can add a tag to your meter in the cme2100 series by sending;
3333;set user.XXXXXXXX="tag one example"
where X is the secondaryaddress of your meter.
if your secondaryaddress is 00012345
you can set it like this;
3333;set user.12345="tag one example"
To be able to see this MOID in a report, you will need to use a report that supports MOID. For example 1112, 2112, 3112.