I found solution for my keyboard... When it pops out to put PIN just tipe 4 digit number and click connect and then press the same 4 digit PIN code on your bluetooth keyboard and press enter/return
Hope you found it useful. Please let me know.
Wow mate you saved me from one big headache ha ha ha I can't believe it bloody worked first time ha ha ha after hours of utter uselessness from Microsofts end and wham you jump out with this one albeit 4 years ago ha ha.
Aah so much stress relieved thank you very much:)