On my view pad 7 (without e) the issue with keyboards really was on the mini usb connector. Several keyboards doesn't work with the first usb-to-miniusb adapter, but switching the adapter, following an accessories seller advice, all keyboard work just fine.
Try with another mini converter and take your keyboard to the store to try it.
Now I'm using a common usb desktop mini keyboard with an adapter and it works perfect. And you can carry that with almost no extra weight in your bag or backpack.
Greetings from Chile