In GetASFStream
1. Click Common -> Detail Setting
2. Select "Local item 1" tab
3. Check "An automatic speed setup is confirmed"
4. Enter the appropriate value into the "Your environment [MBPS]" editbox.
5. Click "Apply"

May be "Fast streaming is used" checkbox on the same tab should also be marked. Who knows?
p.s. Disgusting interface and translation ... but GAF really does what it should.