You can't really ''store'' the selenium scripts in ALM to run, but you can launch them from ALM and report results back. I have seen customers do this before usually you would do it in one of 3 ways.

The 1st way: You would create manual tests in ALM to represent each of your selenium tests then you would kick off your selenium tests from outside ALM, the selenium test would then have api code that would upload the results of the test to the manual test case in ALM.

The 2nd way: Run them in Jenkins and publish the results to HP ALM using the HP Apllication Tools Automation Plugin, for this though they would need to be running in the JUnit, NUnit, or TestNG frameworks, this method creates an external test set type to store the results for the execution.

http://alm-help.saas.hpe.com/en/12.53/online_help/Content/UG/c_integrating_external_test_exec_overview.htm

https://wiki.jenkins-ci.org/display/JENKINS/HP+Application+Automation+Tools

The 3rd way: Each selenium script is represented by a vapi-xp test in alm, the vapi-xp script actually kicks off a batch file in windows that runs your selenium scipt and reports a pass or a fail if the script runs, you could also come up with some checkpoints in the script and post some kind of results file back up to the vapi script for ALM. This way is better than the first method in my opinion because you can actually kick off the run from ALM.

http://eyeontesting.com/questions/12947/how-to-execute-selenium-scripts-from-alm-test-lab.html