Since License and Support are is now tightly integrated with the exact ASE version you install, you need to do the prep work of generating new license keys AHEAD of your installs/upgrades.
Once you have the new license file ready, you can choose option 3 for the initial install and then replace old "lic" file with the new license file.
SAP/Sybase does give you 30 days grace period which should be normally enough for you to do it post install -- just in case.
Check contents of master..monLicense table after the install to get quick check.
Status column should show "ok" and expiry columns should be null.
HTH
Avinash