No luck with this, the name tex_default_progress_slider only appears 1 time in the rco's, under the <ImageTree> of system_plugin.rco
And for the record... the object used for that bars is named <Progress>, in the "rcomage ps3devwiki mod" i renamed 3 of his attributes to:
-progressImageBase
-progressImageSlider
-progressImageBaseShadow
This is where you need to indicate the names of the 3 images of the progress bar

Anyway... back to the problem... that <Progress> object doesnt exists in the rco you need it, and i dont know how to add it and make it work
Also, i dont see any "color filters" tricks used in the other <Progress> objects of the firmware... is still a mistery what the sprx is doing with colors
And btw... there are a lot of <Progress> objects in the PS3 firmware, inside tenths of rco files... in total there are 68 or so (depends of firmware version)