You won't be able to use your onboard flash as a trigger...
The onboard flash cannot effectively be used as a trigger for off camera strobes which use an optical slave such as the Britek and most other studio type strobes.
However, all is not lost, you can trigger your Britek strobes using an inexpensive Yin Yan infrared trigger available on eBay. I have used this trigger for years to fire White Lightning WL-5000, Britek, and other strobes which fire through their built-in optical slave.
The Yin Yan is offered at intervals on eBay but doesn't appear to be offered at this moment. This is the item I am talking about:
Another alternative would be to use a radio controlled trigger. However, the less expensive radio controlled triggers are not as reliable as the Yin Yan IR model. I have been using mine without fail for several years now and will buy a back-up unit as soon as I see one listed on eBay again.
By the way; you will of course need to use your camera on manual exposure and keep the shutter speed at 1/60 second. Although, you can sync hotshoe flashes at up to 1/250 second, you need to shoot at 1/60 second for studio strobes. This is no problem since the very short duration of the flash will freeze any movement.