To move photos in a Picasa album into ACDSee, I open up Picassa and add a tag corresponding to the album name to all files in an album. Then in ACDSee, I search for all photos with this tag and group them into an album. Unfortunately, you cannot preserve the same sequence you had in Picasa – so you will have to manually drag and drop to recreate that sequence. (Note: With Picasa, I never used tags, but now with ACDSee, I am experiencing how my workflow can make use of them quite extensively)