I found out how i can get (almost) ANY iso working. Forget Dax, it sucks.
---PART1---
We are gonna make it in ciso format, so download the tool:
http://rapidshare.de/files/23088738/CSO_tool.zip.html

Now make a folder on your C:\ drive and call it tool. put the tool in it.
Put your .iso in the same folder as the tool (the tool folder).
Now go to start->run..->cmd->enter
type first: cd C:\tool
so we are going to the tool folder.
Now type: ciso X name.iso name.cso
Replace the X with compression level: 1=fast/big 9=slow/small 0=uncompress
So we say "ciso the iso with compression level X and make a second file and call it name.cso where the compressed part comes in.
---END PART1---
so you now have a cso. rename it to .iso
put the iso (renamed from cso) in the ISO folder in the root of you memory stick
You need the new DevHook 0.41d for this:
---PART2---
go into devhook and set the settings to this:

TARGET: (reboot xmb)
UMD iso: your iso here
UMD MODE: ANYUMD
UMD ver: 2.xx -> 2.00
Flash: your fw 2.5 here
CLOCK: 222/111

press start and the iso plays!
---END PART2---

Hope it helped!

__________________