I am using an old baseplate from my rapman extruder as a base for the syringe holder. On top is a printed part that holds the syringe, Ill probably just glue the two together. The syringe goes in from the top and is locked in place by the upper part. The upper part has the valve mounted on it and a tube running true it. At the base is a system on which the rubber plunger with drilled true hole snap fits. This closes the syringe air tight. Both parts need to be fixed together with some kind of clip, I could also use screws but I rather have something that is easily opened to refill the syringe. Will see how this design behaves when we can test it.
The bottom part is finished, the top needs some extra work like screw holes for the valve and I need to draw the clip to hold both parts together.