LOC Simply doesn't work/come on.

Hi there,I am pretty sure I am missing something really stupid here but I really would like to do some IFR circuits of EGKK in the PMDG 747-400 on FS9, just to get to know the aircraft a bit more.I setup the FMC for the arrival and departure airports to obviously be EGKK and manually did four 90 degree turns until I was on the final leg. After putting the 110.90/081 frequency in thee NAV RAD page, you could see the localiser dotted line on the PDF but no matter how many times you press the LOC to try and intercept the localiser, it just doesn't turn on. .. Help? :Confused:Attatched is a view of the cockpit from earlier on the final, with the A/P engaged to control height, speed and heading.Regards.Harry Williams.