Importing gds stream data of the assembly housing packages

Hello

I am trying to import the gds stream data of my assembly housing packages,

My problem is that I fail to attach it to the layer table of my PDK, what happens is that the library of the packages is created but has empty cells.

hence I have to use the "Automatic Layer Mapping", I am not sure if it is the correct thing to do, but I have realized that after completing my layout and then later need to export the gds file of the complete design (including the package) and attach my layout design to the PDK, then I will lose the package data on the generated gds file.

Please see my attached pictures for the setting of importing the gds  packages 

I am using Cadence Virtuoso version IC6.1.8-64b.500.6

thank you

Regards