You’ll need to be able to change the File Type Code and the Creator Code of a file, so I suggest downloading TinkerTool System Release 2. Don’t be afraid if you’re not comfortable with messing around with the inner workings of your Mac- this won’t hurt a bit.
Painter 11 (they’re up to Painter 12 as I type this, but I don’t have upgrade money right now) has a default Mixer pad that loads up fine as a default, but if you clear it, you lose it. For good*. But wait! you say, it’s gotta be written into the application somewhere, right? Indeed it is, but for some silly reason, Corel doesn’t give you access to it again- not on Mac, or Windows.
Go download TinkerTool System Release 2 and then come back to me. Done? Cool. Let’s do this.
First find your Corel Painter 11 application and hold down the Control key and single click the icon. You’ll see the contextual menu show and one of the first options in the list is: Show Package Contents. Select it. Welcome to the stuff you’re not supposed to mess with. Find the Resources folder.
Make a duplicate of a plain looking file called “Mixer Pad.” Put your new copy on the desktop. I had to copy/paste it and then delete the duplicate I made in the Resources folder. Goofy, but whatever. You can exit the Package Contents; you’re done in there.
Open up TinkerTool. Run it in Evaluation Mode – NOT Demo mode. (Then, go buy the application and raise a glass to the developer for saving your sanity.)
Rename the copied file on your desktop “Default Mixer Pad.”
Get to the Attributes pane of TinkerTool and drag and drop Default Mixer Pad onto the File or Folder window.
You now have access to the HFS Type Attributes area. Apply the values below (in caps as I’ve written here).
Type Code: SCRT
Creator Code: ARX1
Click the Apply button.
Now the icon for Default Mixer Pad should look like a Painter icon.
Move the file to your Applications > Corel Painter 11 > Support Files folder for safe keeping and easy access. Double-click it whenever you want the default mixer to replace the open mixer.
Hope this helps and I need to give credit to this forum post for getting me most of the way there – it just wasn’t updated for OS X Lion (the app they mention to change file/creator types will not work in Lion).
*Alternatively, if you hold the Shift key down whilst booting up Painter, it will ask you if you want to restore the application to factory defaults. You can try this too, however, I like having my stuff arranged ‘just so’ and so I haven’t had the courage to try the reset. Apparently you can avoid all the instructions above by doing it this way, but I prefer having the new default file available to me anytime.