From version 2.8.5.5, support for transferring players from Round Robin to a knockout draw has been added. At the moment you can transfer players from Round Robins with 1, 2, 4, 8, 16 and 32 groups. With 1 group the maximum number of players to be transferred to a draw is 128, the rest of the groups have a limit of maximum 4 players pr. group who should be more than enough for normal use. Please note that DfW seeds the players using the same rules as the World Darts Federation. This means that if you have 4 groups for example, the winners of the groups are seeded just like in a bracket:

Group 1 - Seed 1
Group 2 - Seed 4
Group 3 - Seed 3
Group 4 - Seed 2

Round Robin with 8 groups:
Group 1 - Seed 1
Group 2 - Seed 8
Group 3 - Seed 5
Group 4 - Seed 4
Group 5 - Seed 3
Group 6 - Seed 6
Group 7 - Seed 7
Group 8 - Seed 2

Round Robin with 16 groups:
Group 1 - Seed 1
Group 2 - Seed 16
Group 3 - Seed 9
Group 4 - Seed 8
Group 5 - Seed 5
Group 6 - Seed 12
Group 7 - Seed 13
Group 8 - Seed 4
Group 9 - Seed 3
Group 10 - Seed 14
Group 11 - Seed 6
Group 12 - Seed 11
Group 13 - Seed 10
Group 14 - Seed 7
Group 15 - Seed 15
Group 16 - Seed 2

...and so on.

Setup the Round Robin as normal and play all the matches.
Round Robin tutorials:
HOW TO SETUP ROUND ROBIN WITH MULTIPLE ROUNDS
HOW TO SETUP ROUND ROBIN (PDF)
HOW TO RANDOMIZE PLAYERS IN ROUND ROBIN

In my sample I have used 16 groups with 5 players in each group, 4 players from each group will go through to the knockoout stage (a 64 players draw).
I have not put in any results in my Round Robins, but it doesn't matter, it will work anyway.

When the Round Robin has been completed, create a new blank draw with the correct number of players and format (don't set any seeds). You can of course create the draw before you start the Round Robin.
Tutorial:
HOW TO SETUP A TOURNAMENT

When you are ready to transfer the players to the draw, click as shown below:

Set the number of players to be transferred from each group and then select the empty draw from the list of drawsheets.

Any seeded position can be changed by clicking the seed number and then select a new seeding from the dropdown box. Please note that there will be no error checking if you do manual changes. Players can also be replaced by dragging and dropping players from the list of players on the right hand side.

When ready to transfer the players to the draw, click the save button as shown below:

Please note that if you have not opened the blank draw in the "Tournament mode" screen, you will have to open the draw manually after you have saved the players to the draw from the "Transfer Round Robin players to draw" screen.

...done.

To turn of the showing of the seeding numbers, click as shown below: