I did not see the guy. I expected him to be there. And suddenly i seen the flares, I was already in close combat mode. So it automatically locked when i put my nose over it and pressed the lock button. To use the radar missile in close combat mode you first have to switch to the Magic IR missile, press V and switch to the radar missile. In this instance the close combat mode was already engaged. It remembered the mode even after respawning.
Also a good tip. Sometimes after your death and you go back up in the air your radar does not display any contacts. But if you press the lock button suddenly all the radar contacts show up. For some reason it remembers that radar mode as well after your death.