@xpector, I should have updated this post, you're right. My solution was not the most elegant, but it got things running. In this project I've had a Java app starting at the last stage, and I made it run xset, like xset -dpms s off and/or xset dpms force off or something like that, maybe with a delay, I don't remember.
If you solve it in other way, please post your solution here for others. Thanks.