MacBook Pro not detecting new battery

Hi. My MacBook Pro has passed two years and the battery died a few months ago. I have kept it alive with the MegSafe adapter since then with no battery installed.

Recently I bought a replacement battery from a local (Norwegian) battery store, an A1321 Li-Polymer 11.1v 5600mAh.

I tried installing it, but the MacBook would not recognize it. Screenshot >>

Translates to "No batteries available."

At first I thought it was a problem with my MacBook, but I tried re-installing the old, dead battery and it would recognize it (although it would not charge.)

So I contacted the battery store and they sent a new replacement but still no luck. The MacBook will not detect the battery. I have also tried resetting the SMC, but I'm not sure if I've done so correctly; the MegSafe indicator did not change states during the button-pressing.

I know the replacement batteries aren't original Apple batteries, is that my only solution - to get an original?

Thank you,

Erik