Bob McAdam offers some help for exporting SmartLists to Excel using the Web Client at http://community.gpug.com/blogs/bob-mcadam/2014/04/23/bobs-blogpipes
SmartList to Excel with the Dynamics GP Web Client
Reporting & BIExcel & OfficeInstall, Upgrade & Admin
Archived post from 2014. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.