@Mrodfr
For P96 to work you need a "picasso96 settings" file in Devs: (not Devs:Monitor, just Devs:).
On 4.1.1 there is no default file so you should put one there yourself,since i needed some old fashioned (ie:old systems) screen modes I grabbed this one and put it in devs:
http://aminet.net/package/driver/video/ID4-P96After re-booting the P96 utility in prefs will automatically find all those screen modes (defined in that file), and those same screen modes are also added to your screen modes list in the "standard" ScreenMode utility.
Of course if you don't need the resolutions defined in that file you can either delete the ones you don't use or edit them in the Piacasso96 utility.
To delete, drag the string representing the mode you don't need (in the "resolutions" list) over the skull icon above.
In case you just want to change color depth or the frequency in Hz, you can do it right away on the right panel, in case you want to alter the resolution itself (say, you want to change a 320x256 res into a 1600x1050 res) you must drag the string you find under "modes" over the skull.
This way you will get access to the resolutions fields on the lower left (after you set the resolution drag a "new item" in the Modes, now empty, list to specify color depth and frequency among other things).
Finally if you want to create a new mode from scratch, you need to drag a "new item" in the resolutions list (drag the box with the up arrow in the upper left corner) set the resolution fileds, and then drag AGAIN another "new item" in the Modes list too, in order to set color depth and frequency.
Test, and if it works save and re-boot (this new mode will be automatically added to your available screen modes in the standard ScreenMode utility).
Note that some times, creating a similar resolutions otherwise (say, by writing a line in Devs:Monitor Radeon toolType) won't work as it will assume certain other values you cannot specify (such as Sync size) that might not be compatible with your monitor (while adding the res using Picasso96 will produce a working resolution/screenMode), this is of course assuming that your are trying to define a somewhat unusual screenmode (being it because of the resolution you specify or because of the particular frequency you are trying to set), if it is a very standard VGA screen(or multiple such as WXGA etc.) I would advise to use the standard screen modes definition method (in the Radeon monitor toolType or in the monitor tab of the standard screenMode utility, be careful with the "screen interrupts" bug there though).