So, I tried about everything I could think of and were handed to me on another community: still no luck.
I think the flash and trigger just aren't compatible. I do like the flash though. It's a cheap manual flash, which can be triggered in WL mode and has a sync speed of 1/250 on my a580. The build is good for the price you pay: you can buy 4 (!) of these for 1 HVL-43AM!
If anyone has any other things for me to check, please let me know.