companyCreate and query companies with custom fields and externalId

[lounik]

Hi,

I'm using graphQL to add/edit companies on my shopify. The basic api works as expected by I have some issues when it comes to custom fields (metafield.custom.[mycustomfield]): 

1. how can I save the value of my custom field on the companyCreate mutation?

2. how can I fetch a company by externalId? I tried both companies and company, but neither of them work. I can filter the companies query by name and by metafield, but not by externalId. Similar, I can use the ID (gid) with the company object to fetch the data of that specific company, but not the External Id.