String xmlData; // Your XML data goes here
SDOC__SDJob__c sdjob = new SDOC__SDJob__c(
    SDOC__ObjAPIName__c='Opportunity', // Object API Name
    SDOC__OID__c='006000000018HK6', // Object ID
    SDOC__Doclist__c='a15000000012GQ2', // Template ID
    SDOC__Start__c=true // Generate document upon insertion of S-Docs Job
);
SDBatch.writeRecordDataXML(sdjob, xmlData); // Write XML Data to S-Docs Job record
insert sdjob;