Why can't incoming fax be opened in the fax journal?

Incoming fax, that are shown in the XPhone Client, can't be opened. 

Incoming fax are delivered in the TIF format. On many operating systems is no application (Picture Viewer) for TIF documents set as standard. You can define these as following:

• Drag and drop a fax document out of the fax journal into a folder of your choice
• The fax will be laid down there.
•  Mark the file and rightclick it
• Chose "Open with" -> Chose program -> choose your program of choice and set the cross at "Always open file with set program"

You can open every incoming fax per doubleclick now.