First open the legacy design in your latest version of DxDesigner, then copy and paste between the two projects.
Thank you for your reply.
The problem is this legacy design has over 20 pages schemtics, and it is really not a pleasant job to do the copy-paste thing. i was wondering if there is any more convinent ways to do this, like import a few pages from another design. I know EE7.9.4 doesn't organize schematics in *.sch files but a single database. so I am stucked here.
You can copy and paste schematic pages from the navigator view, just select the pages you want to copy from the legacy project (once converted) then paste into the navigator view. If you wish to replace a sheet with one of the 'legacy' sheets then select the sheet in the 'new' project (say sheet 1) and copy sheet 1 from the legacy design and this will replace the sheet. If you don't want to replace a sheet make sure no sheets are selected in the 'new' project.
There is no mechanism to import the ASCII files directly into an existing design.
Thanks, problem solved:)