I know this is a really old post, but it still came up early in the results for me. The solution I found is that you have to change the TYPE for AHTML reports.
In other words, this works for Excel:
TYPE=REPORT, COLUMN=N5, WRAP=4, $
But in AHTML, to get it to wrap, you have to use TYPE=DATA:
TYPE=DATA, COLUMN=N5, WRAP=4, $
It's silly that this is the way it is, since it's completely non-intuitive, but it's a workaround.