OK, so i finally had some time to dig into this.
@johnpoz:
According to your state table pfsense sent the syn, but your machine didn't answer.. Sure that machine is actually listening on 3070?? Great you opened the firewall, but if nothing listing never going to work.
Oh man, that was it. These port checker websites of course assume there is already some application listening on the specified port. I tried PFPortChecker from Portforward.com (nice little tool btw.) and everything turned out to be working just fine :)
Thanks for your help!