VAB docking ports don't work

[Damianoid]

I'm not sure if this is due to mod or if its a vanilla KSP issue but I've noticed that whenever i try to attach something to a spaceplane by a docking port (specifically the cargo holds in the B9 aerospace pack) I can't get the ports to link up like they do in the VAB. Its a real pain as what's the point of a cargo hold if you can't load it up with stuff to drop in orbit?

Has anyone else experienced/has a solution for this?

[Damianoid]

Sorry, just noticed the title should say SPH docking ports dont work.

Brain fart, my bad

[Kimberly]

In the VAB, docking ports are treated like decouplers. In flight, docking ports act like, y'know, docking ports.

[Damianoid]

No I mean that when i try and place two docking port against each other, intending to decouple them in orbit they wont connect properly in the SPH