Transactions using iBase Driver (CI 3.0.4)

Hi Guys, 

I've been working with Firebird 2.5 using ibase DB driver on CI 3.0.4.   I sow that transactions is not working with that driver.   It seems to not rolled back at full the queries between trans_start and trans_complete.  It used to work properly on CI 2.2.0 with firebird driver.

Well, in order to keep my system working I hacked CI 3.0.4 copying the full database folder I have from CI 2.2.0.   So I returned to work with the old dabase driver. 

Is there any solution for this problem ?  Am I doing something wrong ?    I'm CI happy user for 6 years.