firearms certificates in northern ireland

Hi all,

I live and shoot deers in the Republic of Ireland (mainly fallow with a .243)but am only a couple of miles from the border with Northern Ireland. A farmer has recently approched me to cull deers on his land in northern ireland. I was wondering what are the procedures for getting my rifle lisenced to shoot deer in Northern Ireland? Who do i talk to? What do I need etc.

Thanks in advance for any help.