Hehe, just downgraded to 3.03 OE-C so I can play around with this too :)

Well, I found out what the values 4-7 are - they're strengths of the individual channels.
Doesn't seem to affect topmenu's xmenu though.  I tested it with the loading circle image.
Valid values are from 0 to 1, so 0.5 means "half" strength.  By default, it's always 1, meaning nothing's changed.

4  - Strength of Red Channel
5  - Strength of Green Channel
6  - Strength of Blue Channel
7  - Strength of Alpha Channel


Also, with the hex values, it seems that it will always start at item 14 (that is, item 14 is the first hex value).
It seems to contain all sorts of weird values   Though as for xmenu, it contains pointers to the "native" table:

16  - "native:/OnXmbInit"
19  - "native:/OnXmbPush"
21  - "native:/OnXmbContextMenu"
23  - "native:/OnXmbCursorMove"
25  - "native:/OnXmbScrollIn"