Theres nothing to conduct heat away in space if you have good insulation, so surprisingly enough you can actually cook in your space suit if you cant radiate that heat away. Your suit insulates you and prevents that. Without turning this into a giant science discussion, your thin flightsuit if it has the right materials, will keep you warm in space. This is because the heat cant radiate away from your suit faster than your metabolism can keep up, even if it is -459.67 F. As soon as you introduce an atmosphere to conduct heat away then you start having issues. Its why you would need a powered suit and thick insulation on surface.
Also: If you want to get into theory crafting, I worked with some really cool stuff recently that had a high thermal resistance and is like a carbon ceramic foam, shit they used on the space shuttle but better and cheaper. With the advancement in material sciences, its absolutely reasonable to think they have found a way to create a thin spacesuit capable of keeping your body temperature regulated even in solar radiation.
Pertinent links to read if you care to:
Most heat resistant material
Thermal radiation Wiki
Black Body Wiki
Slate.com: Can you survive in space without a spacesuit?
Just to add, I just understand the basic concepts of some of this stuff but maybe one of the smart kids can explain it better.
