Use workflow-send button without using Form Builder/Runner
I have a custom form that I wrote manually without using Orbeon Form Builder. I want to save the XML file to Alfresco when the form is submitted. This can be achieved with forms created with Form Builder using the workflow-send button. My question is how to use this button with forms that were writtin manually.
That button and the Alfresco functionality are part of Form Runner and they were not meant to work independently. This is not to say that it's not possible, but you will have to look at the source code and get at least a minimal understanding of it.
The place to start for Alfresco support is alfresco-model.xml. You might be able to start by including this model with XInclude in your own form. Then, that model has at least a dependency on an instance called fr-parameters-instance which provides the form and app name. This is used to read configuration properties.
The second place to look is persistence-model.xml, which is the place which actually uses alfresco-model.xml.