Joining aluminium extrusion lengthways

[EddyCurrent]

The picture shows a proposed sliding table for a saw bench. Three aluminium profiles 40x80, 40x160, 45deg. side by side with 6mm aluminium top pieces. The width across the top surface is just over 300 mm, total length of the assembly will be 1250mm. As you can see it's fastened to two SBR rails with four bearings fastened to the machine.
The question is, how can I join the aluminium profiles together along their length ? I've looked on Motedis web site but can't see a suitable connector.



You can see the 'proper' sliding table here; http://www.hammerusa.com/us-us/produ...ner-48x48.html
and here if the video works for you; http://www.hammerusa.com/videoplayer...hiebetisch.flv