As it would the customers primary occupation. Be careful to probe if the customer has a part time occupation or job. This might be the reason the customer needs to insurer a van. There primary occupation might be irrelevant.
As an example the customers primary occupation is a Teacher, however they also have a crafts business where they make and display items at the weekend. This is all done on parttime basis and the customer needs the van to carry these items. This is the reason they have purchased the van. Not for the teaching job.
To add this you would simply select the occupation, employment status and business type, like you would the primary occupation.