Hi there and welcome to ECN. Normally we don't encourage people putting links in here, especially if they are new. However, seems you aren't actually selling anything and your place is electrically orientated, it's all good.
Wire 2 of the 120V windings in series. As long as it has insulation rating to handle the 240V it should be fine.
One use of such a transformer would be to stepping 120V (2 windings in parallel) to 240V center tapped. I'm still looking for one to do this that is integrated with an enclosure where I can put a 6-15R or C13. And I want to keep it small so I can carry it with me.
A very common transformer with 2 120V windings and 2 240V windings (commonly used to step 480 down to 120/240) would not work for me, since my goal is to get a center tapped output (120V or 240V) with a 120V input.
#205573 - 03/10/1205:11 PMRe: Great Electrical Power Engineering Forum
I don't need more than 100VA ... light weight so I can carry around with the netbook I power up with it where I need to when the battery runs low. This is so I don't have that 120 Hz vibration feeling on the surface in front of the keyboard around the mousepad due to the fact that the unbalanced power the 120V normally has will be capacitively coupled across the power adapter and raise the voltage level of the DC side by 60 phantom volts relative to ground.
It looks like that catalog does have something I might be able to use, if I can find a suitable enclosure for it to mount a receptacle and either grommet a cord or mount an inlet.