FM 13 Editor-how to enable lower German league?

Dear all,i am not expert in using the editor in football manager,so i decided to ask a little help from you.
i want to enable the German regional liga in game,which is the tier 4.
now i open the editor and enable the regional liga,the problem is when i start a game i got the message that the game allows only two teams to be relegated from the third division to the regional liga.
i tried to modify the number for the german 3rd relegation,but it won`t let me do that.
can anyone please be so kind to help me with this issue?
thank you in advance.

this one is tricky, i had the german league all the way down to league 6.
you have to change the relegation and promotion from the leagues, change league 3 to 3 relegated, and league 4 (if they are still the 3 regional leagues) to 1 each, that way only one team from, south, west and north will go up. change their relegation to 1, league 5 make one up and same for league 6, this took me many hours of fiddeling and making new leagues and cups.
in the end i had 6 german divisions, dfb pokal (all 6 leagues plus 10 none league), liga pokal (the entire first division) german super cup (first division winner vs dfb pokal winner)
the german winners cup (the 6 division winners)
changed the money you get for each round, and winning plus the reputation of the cups to make them more worth winning.
downside, i have a 5th division team with a 69.000 seater stadium and the team has 80million in the bank lol, and bayern munich are worth 29billion, i think i kinda added to much winning money hehehe.
and as i dont like the english prem, i changed them to amature leagues wich is fun, cause now players that where worth 40mil are now worth 40k hehehe. just try to mod as much as you can, the editior will always notify you of problems that wont let the game work, so take note of it, and try to fix it, the editor aint really made for quick fixes, just take your time with it, after all the first timr around it too me 3 days to get the german legue fixed.