auto index in Apache

Please excuse me to post this Apache related question here, but I think most of you might be very familiar with Apache web sever and I couldn't find a Apache forum. In Apache, The index of a directory can come from one of two sources: 1. A file written by the user, typically called index.html. 2. A listing generated by the server. The other directives control the format of this listing. My question is: if I am using the second method (i.e. using the listing generated by the server), how can I increase the maximum length of the displaying names for the files? We have some files with long names, and the displaying names (not the URL) will get truncated if we use the second method. So, is there a way to increase the length for the displaying names? Thank you very much in advance. George