webdavs since openSUSE 11.3 extremly slow

I want to access a MS-Windows file server with a linux-client with webdavs via internet. As webdav-client I use dolphin and konqueror. On the file server Microsoft Internet Information Services, version 6.0, is installed. The webdavs-server offers me a SSL-certificate, which I accept permanently in konqueror. In openSUSE 11.3 or 11.4 the browsing through the folders and copying of files takes very long. Even if I install the latest updates/patches in 11.4 the problem is still there. In openSUSE 11.2 or 10.2 I have no problems (no matter if I install updates/patches or not). Does anyone have the same problem? How can I solve it?

kind regards,

Tobias from Germany