I read the datasheet too, it doesnt really specify a continous rating, ie not pulsed.
For a power rating of 3w though at a vf of 3v, a 3v supply isnt really high enough for a simple resistor type current limit, 4 'd' cells would give 4.8v if they are rechargeables, and to get 3w a resistor of 1.5 ohms would be needed, at 4.8v.
Be aware though this led might not be intended for continous operating, email osram technical and see what they say, I suspect you'll have to run it a bit lower wattage, a 3.3 ohm resitor would run the led at half power.
Also this led will need a heatsink,maybe a piece of ally in good thermal contact with the housing.
Safety: You may have noticed that a 3w white led is rather bright and can leave yellow dots in your vision, this led is the same but you cant see it which is worse, treat the led the same as you would a visible white one, point the led away from you all the time its powered, dont stare into it to see if you can see it lit, you wont but your retina's will, put a red visble led on the finished item to show its operating.