Papaerclip file name and special characters

Hi
I have a problem checking the uniquness of filename. My rails
controller code is

if params[:document][“attachment”] &&
(current_user.documents.find(:all).map(&:attachment_file_name).include?
params[:document][“attachment”].original_filename)
flash[:error] = “File already exists”
else
#store file

    I am using database storage. Now suppose if I am saving the file

cli ent&&list.gif paperclip save the attachemnt_file_name as
cli_ent_list.gif
Again I am trying to upload the same file and in the above code it
goes to the else part and save the file since
params[:document][“attachment”].original_filename will be
cli ent&&list.gif

I cant use validatesuniquness because of some reasons and have to use
the above code. Please tell me how can I solve this issue?

Thanks
Tom