Composed primary key use wrong base_field for relationship

Problem/Motivation

I need a view using a relation on a target table having composed primary key (actually locales_target with lid and language has primary key) .
When creating the view the relationship is using the last column composed the primary key, these make the relashionship failed

Steps to reproduce

Create custom Table on locales_source and locales_target
Create relashionship from locales_source to locales_target
Create a view on locales_source using the relation

The Join is using locales_target.language as relashionship

Proposed resolution

Use the first Primary key found in the table structure (lid)

Remaining tasks

Make the relationship field custimisable in the relationship configuration form