Since I didn't want to adjust more than 160 transitions manually and Premiere doesn't have a "Dip to Mute" audio transition either I came up with a workaround:
Instead of using "Dip to Black" you can use "Cross Disolve" that you attach left and right of the clips. If you are using the mouse you need to press the Ctrl key to force the full length transition in case you don't have enough handles.
Since I want to fully use keyboard shortcuts to automate the process using AutoHotkey all my single clips are trimmed in the trim window, numbered in order so I can just drag them all together at once to the timeline. Then I run the macro using the follwing keys to be sent.
1. One time go into edit mode: Either use T and then four times Shift + T to go into right trim in mode on the nearest edit point or create a keyboard shortcut for "Select Nearest Edit Point as Trim In" In Preferences Keyboard Shortcuts and use this shortcut.
2. Ctrl + Arrow Right to trim one frame. This needs to be done so that teh default transitions are applied to the end of each clip.
3. Crtl + D to apply Cross Desolve (Default) and Ctrl + Shift + D to apply Contant Power for the audio track to the left clip
4. Arrow Right to move editing point one frame
5. Again Crtl + D to apply Cross Desolve (Default) and Ctrl + Shift + D to apply Contant Power to the right clip
6. Ctrl + Left Arrow to trim one frame left and close the gap again.
7. Loop with Arrow Down to step 2 until done.
In my AutoHotkey macro I use an inputbox to enter the number of edits for the loop. Now I just call the macro enter the number and in a few seconds all transitions are placed.
I'm using a similar strategy to automatically render each section as a separate clip for the DVD authoring. This way I can easly change a clip and markers are automaticlly created in Encore when the clips are dropped in the timelline. To be more flexible and have more control over the sections I'm using markers in Premiere. In the macro I then use Shift + M instead of the Down Arrow. Work that lastest for three days is now done in a few minutes. I also created a programm that creates my titles from a text file in a second.
I would like to see this kind of support from Premiere out of the box. Call me old fashined, but any tool should support what we need to do instead of having us to tweak the problem to make it fit the tool.
Marcus