I do the same thing with Robert's eSearch to export a CSV file of addresses. While I don't have a way of creating the mailing labels within the Flex app, I use a Word document with a macro that reads the CSV file and formats the labels.
I've attached the documents in a zip file. There are two versions of each of two documents since the macro code depends upon the version of Word, ostensibly Word 2000 and 2010 (should also work for 2007 but I have not tested it). Then there is a version for Owner Addresses and a version for Resident Addresses (no names), since they have different sets of fields. In each document there are buttons for a choice of labels (Avery 5160) or post cards (Avery 8387). Anyone who wishes to use these will need to modify not only the Word document form but also the macro code, particularly to set the field names used.
Marc