Hm, a radar... the following just came to my mind, it's just some rough ideas, but i hope it's something that can be built on...
Say you've got a texture for the Radar and a (small) texture with a white dot for the Players on the radar.
You could use the foreach RadiusActors function:
foreach RadiusActors( class BaseClass, out actor Actor, float Radius, optional vector Loc );
Iterates through all actors within a specified radius of the specified location (or if none is specified, this actor’s location). // Quote out of the Language Reference
This way you get all Pawns, or whatever you want, within a certain area (specified by Radius).
Then compute the distance between the Player and the enemy (let's call this var "EnemyDistance"). This is a vector with an X,Y and a Z component. Forget Z ( or use it if you want to make a radar like the one in CounterStrike...).
Now compute ratio=RadarRadius/Radius // Radar Radius is the size of the radius of the circle of your Radar Texture.
Now Ratio*EnemyDistance should give you a nice little vector, whose X and Y components can be used to move the "dot" texture around.
E.g. compute where, on the canvas, the middle of your Radar is, then add X and Y to these Coordinates, and draw the white dot.
I haven't tried it out, maybe it's complete nonsense, but I think it's worth a try.
You could put the "RadiusActors" call in a Timer() function, save the "EnemyDistance"-variables in an array-var, and then use the array to draw the white dots...
Hope this helps you!