There are two approaches, pick the one that works for you.

1) Just prior to turning the lamp OFF, take it back to 20%. When you turn it ON the next day, it will come on at 20%.

2) Turn the lamp ON, then two sets of 16 dims to absolutely guarantee that the lamp is at 0% brightness.
Then issue a bright command with the desired repeat value to take you to 20%. 30 minutes later issue additional bright commands to take it to 50%. Finally, after an additional 30 minutes, issue the last bright commands to take you to 80%.

In all cases, make sure you use the Dim/Bright command with the correct repeat value.

In example two, your code would look something like this:

IF Time of Day = Sunset
Then Transmit X10 A/1 (select your H/K code)
Then Transmit X10 A/Dim, repeat 16 times
Then Transmit X10 A/Dim, repeat 16 times
Then Transmit X10 A/Bright, repeat 7 times
If Time of Day = Sunset + 30 minutes
Then Transmit X10 A/Bright, repeat 9 times
If Time of Day = Sunset + 60 minutes
Then Transmit X10 A/Bright, repeat 9 times

Dan Boone, ADI