Generating filename when storing a file

Hi all,
I am new with Developer and have a question that I think its solution is easy but i do not know how to solve it :slight_smile:
I have created a flow service containing pub.xml:documentToXMLString and another service pub.flow:savePipelineToFile. The idea is to fill a document and then to store it onto the local HDD. Everything is OK except that when I am using the savePipelineToFile-> Service In->fileName it is hard coded and when i publish two or more documents the xml file contains only the last one, it overwrites the previous ones. How could i generate the filename for every filled document?
Thank you in advance for your helpโ€ฆ

use current time stamp to the file name extension, so you can have all the files.