I use Hotkeynet. It took a little more work to setup then ISboxer but it works just fine for me. Half the fun was setting it up to quad box in a comfortable way.

I'm not familiar with Pwnboxer but for setting up hotkeynet here is a few things i had to do that may apply to pwnboxer.

First game launched is using the blizz launcher
other games are launched using the diablo software (the D3 icon, not the launcher icon with -launch added)
You can use multiple installs with simlinked data, it may not be necessary and in my case caused some issues while rifting that were solved by using regular installs.

Good luck, i hope you get it working as its a lot of fun boxing this game. Takes me back to my D2 days when i ran several clients.