Lactate Threshold - where do you set the LT pace?

Hey folks

So I've had a VO2 Max test in a lab last week, including a "proper" Lactate Threshold test (blood samples).

Until I had the test, I used to have the F5 set to "auto detect" Lactate Threshold. Now that I've got actual lab results for LT, I've turned the auto-detect feature off, however I have 2 questions:

1. I've found how to set the LT heart rate manually in the watch but where do you set the LT pace? My current LT pace is 0:15/km slower vs. my lab results as it was auto-detected by the F5 and just stayed at that mark...

2. Given that I have lab results, should I turn LT auto-detect on or off?

On a related note, the F5 calculated the same VO2 Max as I got in the lab. Given the criticism of VO2 Max estimates using fitness watches, the F5 did a pretty good job with a sample of 1!