Flash speed x100

[Hansm]

Hi,
My first post here, so first let me itroduce myself.
My name is Hans, living in the Netherlands close to Nijmegen.
i have a part time photography company mainly wedding and portrait photography.

A few months ago I bought a Fuji X100. I'm very happy with the results and the latest firmware UG did a great job.
Since I also want to use it suring Weddings I also bought a Fuji flash the EF-42. Reading the camera manual it states on page 33 that the flash speed is 1/2000. However when I power on the flash the speed does not change to 1/2000 but keeps the same as whitout the flash on. I use aperture preset. Speed on the A dail. Red eye reduction is switched off. In fact so the flash is now set up as fill in flash witch is fine in most cases but sometimes I would really have the speed to 1/2000 to reduce the effect of the ambient light. Till now I could not figure out how to set it up like this. Does anyone have experience how to set it up this way? As far as I get now is to set the exposure also to manual and 1/2000 but I get the impression that somehow it should be possible in A mode also.

Thanks in advance for reading and suggestions.

Best regards

Hans