How to fetch attribute of contenttype in customer portal (Oracle Knowledge)

Summary

We created a contenttype (for url's) with a selection attribute 'open in new window'. We want to make a function in CP that targets the URL to a new window based on the value of the 'open in new attr.

Content

We created a contenttype 'URL' which contains a 'title', 'url' and 'open in new window'-attributes. This gives the user the possibility to add links to their customer portal interface:

title - url - open in new window:
how to do this - http://www.url.com/how-to-do-this.html - yes
how to do that - http://www.url.com/how-to-do-that.html