You can setup your assignment so that solutions become available to students after a pre-specified number of submissions.
To use this feature, first go to "Submission" section for the part and set "Show Solution" to ON. An option will appear that will ask for the number of submissions after which students can see the solution
Add all the files that you want students to be able to download in the solution subdirectory under asnlib for the part
After the specified number of submission attempts, students will see an option under Action menu to download the submissions. If the students selects this option then a zip copy of the solution directory will be downloaded to their computer -