Syncing OF against an own hosted webdav - password is not stored in keychain

i’m using OmniFocus 2.4.2 on my

  • iphone 5
  • macbook air (10.11)
  • Macbook Pro (10.10)

I’m having also a apache/webdav running on my local network at home which is protected via username and password. I have no issues to sync OF with my iphone and with my Macbook Air. But when i try to sync my MacbookPro i’m running into the situation that the OF is asking every time for username and password. After type in the username and password the sync is running successfully. But the username and password is not stored within my keychain. When i sync again i see the username password dialog again. I added the credentials manually into my keychain but this will not solve the issue. The only difference to my MacbookAir is

  • The MacbooPro is using OS X 10.10 instead 10.11
  • The keychain on my MacbookPro is stored on a usb stick

Does have any other from you similar experience or issues with syncing the database.