Very interesting. My HTC/Aces High II/skins/p40e directory had 69 files and the last one alphabetically was TRIM.bmp.
I went into AH2 and resaved the P-40E skin, shut down AH2, and then looked again, and now there are 96 files there and the last one is USSTAR1_a.bmp.
So apparently my first "save" of the skin didn't extract all of the files correctly...
Thanks for your help, Kev!