Thanks for your answer!
Ok... after a hard research and thanks to other users of this forum I think I get the free way to upload custom scales to our prophet 12.
This is a quick tutorial:
First We need Scala software:
http://www.huygens-fokker.org/scala/In this software we can make our custom scales or load a lot examples that easily you get it around the net.
1 load the scale
2 in the command space write: set synth 107
3 save normally
Now you have a .scl file
Now we need to convert to .syx file, you can do it in this web
http://www.microtonalsoftware.com/scl-scala-to-mts-converter.htmlOnce you get the .syx file we will have to change one hexadecimal number of the file in order to said to the prophet what is the place to this scale...heh...we have 17 custom scales inside the synth if we want to upload one scale in the third place we have to change one hexadecimal number....
ok
we need this software
http://ridiculousfish.com/hexfiend/1 load the .syx file
2 change the second number of the second file from 00 to other hexadecimal number between 01 to 16 in hexadecimal
3 save
4 upload this file to prophet
This last part is very tricky to describe but....I attach this guide that other user made it.... you will change only the tt number.