Following current rules, here is how to braille the section labels:
Use cap A for the "A" and cap T for the "T" -- no ELIs since they do not stand alone. [NC Sec.27.g]
Use double-cap II for the Roman numeral. [NC Sec.18.a]
The "dot" is considered to be a decimal, which is a numeric symbol, so it requires the use of the multipurpose indicator as follows: after a letter and before a decimal; after a decimal and before a letter. [NC Sec.177.ii and 177.v]
Unfortunately, this makes for a very long construction.
If these references occur [u]frequently[/u] throughout your transcription, I don't think it would be frowned upon to write a note on the Transcriber's Notes page stating that you are omitting the decimal points from the section labels. This would make them slightly more compact and a bit easier to read. Like this:
Note that a dot 5 is still required between a letter and the following number, otherwise the number becomes a subscript.
print: AII.4.a et al.
[braille],A,,II".4."A ET AL4
[braille],A,,II"4A ET AL4
I hope to hear a loud objection if this is considered to be bad practice.