Nav

Is there a way of getting a textual/string version of what is returned by the following code:

wp_list_categories('show_option_all&orderby=ID&show_count=0&title_li=&hide_empty=0&exclude=1,2');

Why I need/Explanation: I have WP in a site which also integrates other software, I have used the require(.\wp-blog-header.php’) function so that I can use the wordpress tags and posts within the pages, however on some pages are causing conflict (i think that a class is called the same in both applications). if I remove the require statement th pages work fine but these pages cannot use the navigation bar I have created (this is the only information required by wordpress for these pages)..

SO, what I want to do is call the list categories function and then store the output HTML within a string which can be used globally so that on the effected pages I can still use the WP generated nav bar (I do not want to manually create the nav bar in case I/User changes the name of the links etc)

If anyone can help it would be great!