I have found the following possible solutions
From PowerDnn support
The workaround that I've used previously for this issue was to create another portal alias using subdomain structure (xxx.xxxxxxxx.com). It'll have to be created in the control panel Websites and Domains > Domain Alias/Site Alias as well as on the DNN installation Host > Site Settings > Edit the portal > Site Aliases.
Fortunately, doing this still lets visitors come to the site using the subfolder structure. Only accounts that need to log in will have to use the subdomain structure, so people won't have to change bookmarks or anything and search ranking needn't be affected.
Also check this out
http://stackoverflow.com/questions/...om-a-child