You can get your system_plugin_fg.rco working again without screwing up functions in your XMB.
All you do is get "RCO Icon Editor v1.14d For PSP" (from ps3news.com/forums/attachment.php?attachmentid=10220) run it open topmenuplugin with RCO editor and extract all contents get the decrypted Topmenuplugin, and click on replace all and bingo topmenu should be done do the same thing to what ever you want of naruto theme like sound bar battery bar waves etc. Brief guide:
1. XMB - The main menu of the PSP.
2. system_plugin.rco - Click sounds when you scroll
3. photo_plugin.rco - photo loading icon & folders
3. game_plugin.rco - game loading icons & currupted icon
4. savedata_plugin.rco - Savedata loading icon
5. system_plugin_fg.rco - Battery icon
6. impose_plugin.rco - Volume Bar
7. opening_plugin.rco - start up sounds/word/bootwave (when you turn your PSP on)
8. gameboot.pmf - short video clip when you start a game & hombrew app
9. 1-12.bmp - Month theme colors
10. system_plugin_bg.rco - Backgroung Waves
11. topmenu_plugin.rco - Menu Icons (photo, Music, Game, Video, Setup, Network)
12. Bootwave - opening wave (also when you turn on your PSP)
13. ltn0.pgf - This is the font that displays only on the XMB and Web browser (not in a UMD)
This Shadow Removal that I compiled which is really nothing but blank images should do the trick. Just use RCO editor 1.4d and go replace all and click on the file where you extracted all the stuff inside.. and presto all your shadows well be gone.