Firefox GP only works with Frifox Profile

Hi, i try to use the firefox Policys to konfigure startpages etc for WIN 10 VMs. When the User logs in there is no FF Profile in app Data. Starting ff for the first time, the startpages dont appear like i configured, but a Profile in appdata will be generated. Starting FF for the second time the Pages appear, like configured. So the ff GP only works with a Profile in appdata! But with VMs the ff Profile will be deleted after logout. Can i automatically generate a ff Profile while login in windows, without starting ff two times? How can i do this? This would solve my Problem ? Any other workarounds are welcome! regards! Jontef