This is definitely possible without customization.
The first thing you need to do is build a process that has an IN variable of type Document.
Then set a watch folder endpoint on that process so you can drop the file on the file system. It'll then populate the IN variable of type Document with the content of the file (xml). You need a document variable for later when using LC Forms, otherwise you could use an XML type.
In your process, you'll need to create a variable of type xfaForm and initialize it to point to your xdp in the resource tab. This is the form the user will see in workspace. Also you'll want configure the render service (under Advanced Settings) to point to the Sample Forms/ RenderPDFForm. Set the data parameter to be the document variable that contains the xml. If the xml is in the right structure, then it should populate your PDF properly.
The last step is to add a User operation and assign the xfaForm for the Input Form variabale.
I've entered the path for the watched folder and of course all the other folders are created by the system such as (input, failure, result, preserve, stage).
After I chosen Operation name to be "invoke" I had to configure input parameter mappings, so for the variable IN I've entered *.xml value (so it is looking for any xml file to assign to IN variable)... I would send you the PrintScreen shots, but I can't send it to the forum. :-(
You have two IN/Required variables: initForm and IN but seems that you're only dropping one file in the watch folder (by looking at the watch folder settings). That would create a problem since it expects two.
Remove the "in" and "required" property of the initForm variable and see if that gets you through.
You dont need to buy another qpac to do that. Go under the Attachments and Notes section on the User operation. Select the option Copy all notes and attachment from and then specify a list variable that contains the attachments.
Add a set value operation to be the first step in your process and use xPath to add the image from the image variable to the list using something like /process_data/myList = /process_data/@myImageVar
Actually, the Avoka AttachFileToTask attaches a file to a task, rather than to a the Form itself, so this won't help you.
If you want to attach a picture to a form, you can either:
1. Use the LC Forms component to attach a file when you do the Render operation.
2. Create an ImageField on your form, and use Avoka's LC-ES ImageInserter to insert the image directly into the data of the form, and then bind it to your Image Field. This way the image will appear inside your form, rather than attached to it.