Unknown at this time. Has not been fixed in UP1
Change the order of the applications in UAG to list File Access application before Remote Desktop Services.
It seems to be a bug in UAG when you try to publish File Access and Remote Desktop Services on the same server. When you add applications in UAG and you add RDS before File Access you will see the following warning in the Web Logs of UAG. Also, when you try to access the File Access in portal from a client machine then you will see an error " URL /Filesharing/ contains an illegal path ".