Hmm. I don't see it. I am using 5.4 and I do not see it.

I have also attempted to add it to a html module with no luck...

Thanks in advance

I liked Jon V's approach with banner module, worked for me at least.

The case is that every time you put the Adsense code into the HTML module, it is reformatted into a long single line, which doesn't seem to work. In the opposite, Banners module keeps the lines in the code untouched (which is essential).

Hope this helps!