In transit export sales from other state

Dear All,

I am registered exporter based at Delhi. Now matter is that I have got order from Nepal for supply of Steel to them. In India Steel gets at cheaper rates from kolkata. I have made a purchase from kolkata. I am inviting suggestion from you all on following:

1. Can I take purchase against Form-H from Kolkata or Ineed to go only on C-form.

2. Can I send material directly from Kolkata to Nepal via Bihar

3. What document I need to provide to transporter for flaw free movement of goods...it will be better if I get notification or rule reference so that evidence of movements can be shown to sales tax dept during transit.

Looking forward for urgent and valid reply from experts

Thanks & regards, PB