Yes Guys its POSSIBLE!!! I can confirm that its working. BUT proceed at your own risk!
If U have a working 1.1.1/04.01.13_G iPhone unlocked with AnySIM 1.1 this is what u need to do:
1. Run Oktoprep via Installer
2. Update to 1.1.2 via iTunes, after update leave iPhone connected till iTunes "see it" then close iTunes.
3. Jailbreak (http://conceitedsoftware.com/iphone/1.1.2-jailbreak.zip)
3.a Install BSD Subsystem via Installer
4. In Installer add rep.frenchiphone.com or hacktheiphone.com/1.xml to your installer source and then Install AnySIM 1.2.1u from the installer. Reboot iPhone!
5. Put the iPhone in Airplane Mode!!! Run AnySIM1.2.1u! After its completed, go to Settings--->Airplane Mode set to OFF, now u will get a signal bars!
6. !!! IMPORTANT !!!
If u're outside US, SMS and Phone will NOT work,right away tho. To "FIX IT" install iWorld via Installer(in Tweaks 1.1.2), run it, choose your country, reboot(do it manualy if auto doesn't work)
Viola! U're done! Enjoy free 1.1.2! Regards from Croatia!
If for some reason this method is not working for you, follow this to "get back" - http://iphone.unlock.no/#how-to-downgrade-1.1.2