It does not work. The rules give two ways to target spells (barring the ill conceived FAQ entry that doesn't give any clarification): LoS and Touch. LoS has to be direct and "natural vision".
Vision that is paid for with essence counts as natural in this case.
With Radar implants, you never actually "spot" a target. The radar implant detects the target then displays an image map over your vision of the target. It's no different than linking an implanted security camera up to your image link. The data is being recorded, processed, and then fed to you. Sure, it's live, but it's not a natural vision by any means, the image is rendered from scratch by the expert driver. Sight is not the natural way for the sense to be used, just the easiest way for humans to interpret it.
How is this different from cybereyes? Cybereyes are designed to function as similar to human eyes as possible. They simply pass along the direct image being seen to the brain just like a normal eye would. Since they aren't built yet, we can't actually know exactly what is entailed, but we do know that the image does not have to be completely created from scratch because its already present.
Keep in mind that just paying essence for an implant does not make it automatically work for targeting spells. Look at the two ways I've listed above. Cyberlimbs do not allow a character the ability to cast through them (reading the test, only enhancements used to spot work).
No I said that the rules do not say it does not work. That weather or not it works is realy up to how you define sight and is up to your group to decide if does or not. Unless you can point to where the rules say it does not work.
This device emits ultrawideband and terahertz radar in short stepped-frequency pulses. An expert system analyzes the Doppler shift in the bounced signals and converts the information into a three-dimensional “map” that overlays (or replaces) the user’s visual senses.
It makes it extremely clear that this isn't sight. It's a completely generated image that overlays or replaces the user's visual senses. It's not a vision mode. This is made clear both by the implant type (Headware rather than a cybereye mod) and the fact that it lets you "see" (emphasis the book's, not mine). Any attempt to claim it's sight is laughable at best. Comparing it to something like Mage Sight Goggles (which is sight since it's a direct fiber optic cable. It's no different than using a mirror.) is similarly a horrible excuse to let it work.
That said, there is a difference between a computer generated image and a computer filtered image. Sight through cybereyes may be computer filtered and cropped (and enhanced by those different eye mods), but they are not 100% computer generated.