Good way to add connectors to AL extrusion weldment frames.

Hello,

 

I am creating an aluminum extrusion frame in SolidWorks using weldments as a part file. I am then making an assembly from my frame to add all the extrusion connection hardware. I have all the connector hardware stored in a SolidWorks library. Is there any easier way to add all these connectors into my frame without having to manual add the mates for each connection. I tried to add reference mates to my weldment profiles and my connector parts, but it looks like the reference mates do not show up when I actually make my weldment profile part. 



 

Example of type of connection I am trying to make
Example Part created with weldment profile without reference mates
Connector piece with reference mates
Weldment profile file with reference mates.

I am open to alternative options then what I am currently attempting. I am curious as to what people do when they are creating extrusion frames with hardware.