After three days of fighting I have managed to make SG2D to boot Rescatux from its iso file.
Thanks goes to SynrG, dba and chals from #debian-live. And an special thanks to mrud from #grml which did find the final workaround that involved using fromiso.
The current workaround might be improved with a proper solution in upstream so that the loopback.cfg generation on debian live is very easy to implement.
You will have to wait a bit till you see a release that includes Rescatux and Super Grub2 Disk.
I need to fix some details such as having a nice background at super grub2 disk part which it is the main screen that you see.
And… of course… the architecture autodetect feature so that it autoboots into Rescatux 64bit or Rescatux 32bit according to your architecture.