Visa for newborn in mother's passport

Hi!

I and my wife are Ukrainian, we have Tier 2 General Visas (Main/Dependant, correspondingly).
Our son was born in the UK recently. We need to obtain him Tier 2 General Visa (Dependant).
For children under 3 years, Ukraine does not provide own passports/child travel documents.
The baby will be written in mother's passports and all visas should be placed there as well.
We will apply in the UK. How should we fill the Section B of the form
https://www.gov.uk/government/uploads/s ... _04-14.pdf
I mean, should we give the data about my son or my wife (as her travel document will be used)?

And the second question, could we use premium service centres for the application?

Thanks a lot in advance!

Kind regards,
Dmitri.