Screen turns off after a certain time
Ok, I found out the reason for this problem is the band differences on the 3G:

S5830: HSDPA 900 / 2100
S5830B: HSDPA 850 / 2100
S5830L: HSDPA 850 / 1900


And the incompatibility with the current firmware I had (I updated to CyanogenMod 7.2.0 and still had the same issue), so for a quick fix, I went to: 

Settings &gt; Wireless &amp; networks &gt; Mobile networks &gt; Use only 2G networks


And that took care of the issue, however, for a full solution, flashing a latin (like the Brazilian one) with a Modem file like the kp7 or kpl should take care of the problem.