Usually if after setting up the correct driver for your device within Enigma2 and rebooting, if you don´t get the option to set up wireless Lan it shows the device is not recognized during boot up.
I´ve had this with some devices that "should" work, but there device ID´s don´t match the Linux driver ID´s. Best to buy a device that´s known to work.
Some firmware supports more WiFi devices than others.
Another thing to try is uninstalling all WiFi drivers already installed in your image (via plugins, drivers. But only remove Wifi Drivers!! ) and backup your image 1st, just leaving the one you want to use, as they can conflict.