I just used to old trial and error method till it finally changed.
Here's some of the others
WIFI:
Black_0_WifiBars.png
Black_1_WifiBars.png
Black_2_WifiBars.png
Black_3_WifiBars.png
Silver_0_WifiBars.png
Silver_1_WifiBars.png
Silver_2_WifiBars.png
Silver_3_WifiBars.png
Signal:
Black_0_Bars.png
Black_1_Bars.png
Black_2_Bars.png
Black_3_Bars.png
Black_4_Bars.png
Black_5_Bars.png
Silver_0_Bars.png
Silver_1_Bars.png
Silver_2_Bars.png
Silver_3_Bars.png
Silver_4_Bars.png
Silver_5_Bars.png
Status Bar:
Translucent_Base.png
Black_Base.png
Silver_Base.png
These all go in the UIImages Folder in your theme.
I hope that helps some.
Now if I could get my weather to work I'd be done...