Where can I find Galileo almanac files to create custom scenarios?

There are no official published almanac files at this time for Galileo. The N7609B software includes a default almanac file, 20110709_Gal.alm, which is based on simulated orbit data for a Galileo constellation. To simulate a different date/time, you can edit the default Galileo almanac file (it’s a text file) by changing the Week and Time of Applicability values in it. To find the Week and Time of Applicability, this Web site has a calendar that provides this information: http://adn.agi.com/GNSSWeb/Default.aspx. The third row gives the GPS week number and the number of seconds of the week (SOW) as of midnight for that day. The Time of Applicability in almanac files is given in terms of the SOW. To calculate the SOW for a particular time, here is a converter tool: http://www.csgnetwork.com/gpstimeconv.html