When you create a portal and go through it with a minecart the minecart always face East.
No matter what kind of portal you create or in what direction you set it it's always east.
I have tried a portal with wand, One with anchor and direct coords.
When entering the portal without a minecart it behave how it should do.
So there must be something wrong where it don't check the direction of the minecart.
Hope this could be fixed.

Hi there. We're cleaning out the issue tracker since we (mostly me) have mistreated it.

I'm going to close this one as a duplicate to #267 since I'm already looking at that. Entities should behave the same way a normal player would and should be affected by the w:blah:n syntax.