Welcome to Cisco Support Community. We would love to have your feedback.
For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.
Is it advisable to run WEP and WPA2 on the same virtual AP sharing the same antenna?
This shouldn't be a problem, so long as you have one SSID for WEP, and one SSID for WPA2. The antenna itself will not come into play for what type of encryption that is used.