Change letter in hole table

hi,

I need select cell in table and then insert a new letter, for example "F", "T", "J", etc. I would like to define some letters by some holes in a lot of  draws that i have.

This way, the hole "3x10" in all of draws would be "F" for example, the hole "8x12" would be "G", the hole "10x10" would be "T" and successively.

Basically i want creat a specific collection holes each one with your respective letter. I know that i can do it inserting a new column, but this new informations won't be showed in the draw and i don't want it. In other way, it should be possible change it by API, but in the version 2017 it isn't working.

why cant i to change a tag letter of table annotation in 2017 version? For example, in 2015 it works!

Follow a picture that show what i am trying to do.

SolidworksApi macros