One thing I would suggest:

the original plastic tabs had a texture to them, which allowed the glue to "stick" to it. Also, Im not sure, but I THINK the glue dissolved the plastic a little to allow for better bonding. Metal- not so much.

So I would suggest that you add a bunch of drill holes so that when you put the glue in, it gets squeezed through the holes and doesnt come loose. Ever.