How to get a transaction id from a workflow, to use it in the workflow script

Hi,

Can somebody help with the below question?

How to get a transaction id from a workflow, to use it in the workflow script to merge a netsuite email based on the transactionid?

We have tried several formulas like {transaction.internalid}, {transaction.internalidnumber}, {estimate.internalid}, {internalid}. But none of the above fetches any id related to the estimate.

 

To merge the email we're doing

 

var mergeResult = render.mergeEmail({

              "emailTemplateId":123,

              "transactionId":112233

});