We are migrating to Lightning and I've hit a snag with creating a Lightning Action to replace a Javascript button that calls an Apex Class. The button is on a Custom Object called "Sales Order Processing" which is a child record of Opportunity.

The classic button is as follows:

{!REQUIRESCRIPT("/soap/ajax/31.0/connection.js")}

{!REQUIRESCRIPT("/soap/ajax/31.0/apex.js")}

var url = parent.location.href;

sforce.apex.execute("SAASCreateObject","CreateSAAS",{oppId:"{!Sales_Order_Processing__c.Opportunity_ID__c}"});

parent.location.href = url;

This calls an Apex Class that creates a new Record on a Custom Object called SAAS, or updates an existing record if there is one. And it creates a new Case Record that references the newly created SAAS Record. 

I tried the Convert Javascript converter but it didn't work. I tried contacting Support but they were stumped. So I'm reaching out here to see if anyone can help.

Thanks in advance!