Upload files from JCR to IS

Hi Guys,

in a user Task, users can upload files. For the file uploads I will use a JCR SubFolder Attachments Provider.
Now, in a later User Task I have to upload the files to IS for further procession.

The Question is: How can I get the files from the JCR subFolder Provider as an input for a IS Service?

I hope anybody have an idea.

Regards Mario