Modifying an asset's software with asset POST request

I’ve been using the InsightVM API to try to modify existing assets for a site and create new ones using the create asset endpoint: InsightVM API (v3)

I’m able to modify users for an asset with a POST request to that endpoint, but not able to modify software. Is this something that is not supported? Is software inventory read-only for the API, and only able to be changed by a scan?