What is the solubility of oxygen, nitrogen and hydrogen in liquid CO2
at room temperature under its own vapor pressure?

Under normal conditions carbon dioxide does not exist in the liquid
phase it sublimates directly from solid to gas.  Hence, solid carbon
dioxide is called "dry ice."

When stored under its own vapor pressure (58.5 bar at 20C) it's liquid.

http://encyclopedia.airliquide.com/images_encyclopedie/VaporPressureGraph/Carbon_dioxide_Vapor_Pressure.GIF

When CO2 stored under its own vapor pressure (58.5 bar at 20C) it's
liquid, which is called Supercritical Fluid.
When commixed, H2 and/or O2 can be solved in CO2 in any ratio, whether
in supercritical or compressed condition. It's a general knowledge, so
you can hardly find any document.

When CO2 stored under its own vapor pressure (58.5 bar at 20C) it's
liquid, which is called Supercritical Fluid.
When commixed, H2 and/or O2 and/or N2 can be solved in CO2 in any
ratio, whether in supercritical or compressed condition. It's a
general knowledge, so you can hardly find any document.

CO2 is not solid under its own vapor pressure.

CO2 is not supercritical either, unless the temperature exceeds 31.1C. 

It's in equilibrium between liquid phase and vapor phase, just like
butane in a cigarette lighter.

And it is not guaranteed that hydrogen, nitrogen and oxygen will
remain dissolved in the liquid CO2. They might prefer to evaporate
into the gaseous CO2 than remain in solution.

Are there any actual chemists among the google answers researchers or
do I need to look elsewhere?