Under Light shape, select Cylinder.
Under COLOR RANGE, check ARC.
NOTE: This is in case you want your light to emit in a given direction
For example, if your flourecent light is close to the ceiling, and you don't want the whole effect of the light intensity to blow-out your ceiling color too much.
Just adjust your arc options to EXclude part of the ceiling, and rotate your cylinder light shape so that the arc dead part is aiming toward your ceiling, and the illuminating part is going everywhere else.
Use this option to create a partial sphere, cone, or cylinder light shape by specifying a degree of rotation. Values can range from 0 to 360 degrees. The most common settings are 180 and 360, the default. 180 is similar to slicing the light volume in half and 360 is the full light. This option does not apply to the box light shape.
Shadowing does not work properly for directions other than Outward. It always shadows as if from a point light.
So keep that in mind when you think you might be able to place it "inside" the geometry of the bulb, because you might get funky shadows, and possibly run into problems.
Just place it "close or near" to the bulb first, then try other placements.
Hope this helps?
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS