Mod_plsql upload size restriction

Hi,
   I am hoping someone has come across this.  We are using the mod_plsql feature from Apache to upload and download files into a specified table with a BLOB column.  It works fine.  We would like to be able to limit the size (maybe a warning or something when selecting a file) of the file that a user selects from their local environment.

Thanks in advance,
Rolando