FileUpload file keeps disappearing on submit

 Hi,
I have a FileUpload control inside an editform of a grid control and after browsing for a file and clicking on a button, the file chosen disappears.
Is there a way I can prevent this? I don't understand why it is disappearing.
Aaron
 the markup code is as follows:

 
 1 <FormTemplate>
2 <table class="supplierheader">
3 <tr>
4 <td>
5 Upload File
6 </t ...