Here are the problems:

1. There are some buttons which are swapped/mapped wrong when using FuSa on the PS3...so I testet all the PSP-buttons on the PS3 and here are my findings:

PSP button - PS3 function

Cross = Square
Circle = Cross
Square = Circle
Select = not working
Start = not working
Home = Select
VolDown(-) = Start
VolUp(+) = L3
Screen-button = R3

...these things can be changed in the config.txt so this is not a big problem,but I hope you can change this in the next version.

For now I changed the following button-assignments in the original config.txt:

[CONFIG]
AxiSwitcher=NOTE
DigitalSwitcher=WLAN
DeadZone=50
POV_RX=RIGHT
POV_LX=LEFT
POV_UY=UP
POV_DY=DOWN
Button1=CROSS > (Button1=Square on PS3)
Button2=CIRCLE > (Button2=Cross on PS3)
Button3=SQUARE > (Button3=Circle on PS3)
Button4=TRIANGLE
Button5=LTRIGGER
Button6=RTRIGGER
Button7=SELECT > (not working on PS3)
Button8=START > (not working on PS3)
Button9=HOME > (Button9=Select on PS3)
Button10=VOLDOWN > (Button10=Start on PS3)
Button11=VOLUP > (Button11=L3 on PS3)
Button12=SCREEN > (Button12=R3 on PS3)

So I changed the config.txt to this:

[CONFIG]
AxiSwitcher=NOTE
DigitalSwitcher=WLAN
DeadZone=50
POV_RX=RIGHT
POV_LX=LEFT
POV_UY=UP
POV_DY=DOWN
Button1=SQUARE
Button2=CROSS
Button3=CIRCLE
Button4=TRIANGLE
Button5=LTRIGGER
Button6=RTRIGGER
Button7=SCREEN > (not working on PS3/PC)
Button8=HOME > (not working on PS3)
Button9=SELECT
Button10=START
Button11=VOLDOWN > (=L3 on PS3)
Button12=VOLUP > (=R3 on PS3)

...for now that is the best solution for the PS3 I think...for others who want to use my config.txt...the "> (....)" are only comments,so don't copy that in your config.txt...

2. The function of the PS-button from the DS3 is not working on the PSP...can you assign that to the Home button on the PSP?

3. The button-assignments from Button7/8 (config.txt) are generally not working on the PS3,but on the PC they do...
In my modded config.txt there is for example Button8=HOME...in this case the button is not working on the PS3,but it would be nice if that works and if it has the function of the PS-button from the DS3.

4. The Screen-button from the PSP only works when assigned to Button12...
When assigned for example to Button7 like in my modded config.txt,then the button don't work on PS3 (see 3.) and also don't work on the PC...I don't know why...maybe there is a bug with the Screen-button?

5. There are no buttons for use as L2 and R2...can you introduce these buttons for use with the PS3?

6. When using Note+analog nub (for the right analog stick) there are up/down and left/right swapped...this is really bad when playing a game,I hope you can switch the axis for a correct use of the right analog stick.

So with my modded config.txt the FuSa Gamepad is mostly usable on the PS3,but the function of the PS-button and L2/R2 are still missing and the directions for the right analog stick are swapped...these problems must be solved in a next version.
I hope you can optimize the FuSa gamepad for the PS3,that there are all buttons from a DS3 controller available on the PSP and that the assignments on the PS3 are all correct without editing the config.txt...so that the bottons on the PSP are the same as on the DS3 controller...

X=X, O=O, Square=Square, Select=Select, Start=Start, Home=PS-button...and so on

And for example the L2/R2 buttons can be mapped on the VolDown(-)/VolUp(+) buttons on the PSP and the L3/R3 buttons could be mapped on the Screen-button + (-)/(+)...that would be nice.

I hope you can add these things in the next version of FuSa gamepad.
greetz puffel