Launch quick create form from classic form

Hi,

I have a custom entity which has a 1:n relation with the Service Activity entity, the custom entity is the child in this relationship, 

I have added a subgrid for the custom entity in the parent(Service Activity) form and want to use a quck create form to add new records,

I have enabled the option "Allow Quick Create" on the custom entity and also created a new form of type Quick Create,

The issue I am facing is from the Service Activity form when I click on the Add New button to add a new custom entity record the quick create form does not load and nothing happens, if i disable the option "Allow Quick Create" on the custom entity then on clicking the Add New button the main form to add a custom entity record loads up,

I think this is probably due to the fact that the Service Activity Entity still uses classic forms,

Is there a possibility of loading a quick create form for a child entity from a parent which uses classic forms

The CRM version is 2016 on-premises.

Thanks