Auto focus lenses and teleconvertor

Wasn't sure where to put this and think I may already know the answer but thought it's worth a try. I'm quite new to photography so sorry if I'm not very technical!
Basically I bought a Panagor Pentax K-Mount 2x Teleconverter for £3 the other day as I wanted to try one out and figured I couldn't go wrong for £3! Basically I'm wanting to use it on my pentax k-x camera with a tamron 70-300mm which I purchased off here a while ago, basically I just plan on using it if I really need to zoom in on something!

Anyway when I've tried it the aperture doesn't show on the camera. It works great and I can take the pictures with manual focus and with the fire without aperture or whatever it is called but it would be handy if it knew the aperture just to make it easier to expose the picture correctly!

It's not a huge issue but was wondering if it's possible for the camera to read the aperture with the teleconvertor on?

Thanks again

The converter needs to have the electrical contact (like those on the lens) to transmit the lens information to the camera. Without the contacts you don't get any aperture Values, so you'r using the camera in manual mode

Yeh I thought that was the case but thought I'd see if there was any way to do it, it's not a huge issue as will rarely be using it and I can deal with manual mode haha!