Artificial harmonics in tablature

I am trying to annotate artificial harmonics in my bass score, but am stuck.
Let's say I fret a guitar or bass at the 2nd fret and grab the harmonic with the left hand at the 6th fret.
I think the standard notation the tab would be:
2(6)
but this is not a legal input it seems.
Are there ways to work around it?
Also I wish I could write something like 2t6 there (a nonstandard notation).