UPDATE: This guide has been simplified from its original version; you no longer need to manually set up copies of your Cache folder for this to work with ISBoxer.
Here it is working:
1. Minimum ISBoxer version
Be on ISBoxer version 40.2.515.1 or later (check your specific version and/or update via Help->About ISBoxer). If you just downloaded ISBoxer, you should already have the right version.
2. Minimum Inner Space version
Be on the latest LIVE Inner Space build, currently that is build 5615. If you just downloaded ISBoxer, you should already have the right version. You can check your Inner Space build number by hovering your mouse cursor over the Inner Space icon in your system tray (notification area). If it's not right, just close and restart Inner Space to let it patch up.
3. Add Game to Inner Space
Inner Space may have automatically detected your Diablo III installation, in which case it will already have a "Diablo III Default Profile" and "Diablo III - Skip Launcher". If that's the case, skip on to part 4!
Assuming you have not added Diablo 3 to Inner Space yet, right click Inner Space in the system tray and select Add Game, point it at Diablo III Launcher.exe in your Diablo 3 folder.
ALTERNATIVELY, you can skip the launcher by pointing Inner Space at Diablo III.exe, but you must put "-launch" (with no quotes) in the Parameters box. If you do this, you will need to separately run the launcher to patch the game when there is an update.
4. Run the Quick Setup Wizard
No surprises here, just run the wizard.
As of ISBoxer 40.2.422.1, Diablo 3 is now listed in the first drop-down box in the wizard. This will enable the "Make game believe it is foreground window" option when it makes your Character Set, to prevent issues with broadcasting (as described in this thread).
If you are NOT on ISBoxer 40.2.422.1 or later, Diablo 3 is not in the first drop-down box yet, you can either update (under Help->About) or just pick "Other" and manually configure the "Make game believe it is foreground window" option after completing the wizard. Not a big deal. Here's what to do:
i. In the top left pane in ISBoxer, under Character Sets, select your Character Set
ii. In the bottom right pane, check the box "Make game believe it is foreground window"
iii. Export to Inner Space
All standard from there, see the Diablo III Quick Start Guide if needed. Use mouse broadcasting to move.
It may not be perfect. You may run into issues. Report them. Thanks