I don't have version 11, but in version 8 (I guess it will be similar in v11),
1. From the Tools Menu select 'Select Device Control'
2. From the drop down list select 'MS1394 Device Control' then click the 'Options' button
3. Then its a case of playing about with the values. Start with the pre roll time (try increasing it)
4. Enjoy (once you have the values that work for your camera)
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.