Cannot associate existing individuals to new families using individual id

[pfurio]

The new families/create webservice supports creating new individuals (father, mother and/or children) using that same webservice. On the other hand, if individuals already exist, it is possible passing the individual name and the family will contain those existing individuals. However, at the moment, it only works with the individual name and not with the individual id.

It should be supported that users pass in the individual(mother, father or children).name field either the name or the id of the individual.