$filename='testfile';
$req=POST 'https://www.abcd.com/fileUpload.aspx', Content_Type=>'form-data',  Content => [file1=>["$filename"],file4=>[""],file5=>[""]];

##</code><code>##


--xYzZY
Content-Disposition: form-data; name="file1"; filename="testfile "
Content-Type: application/octet-stream
Test File Contents

--xYzZY
Content-Disposition: form-data; name="file4" filename=""


--xYzZY
Content-Disposition: form-data; name="file5" filename=""


##</code><code>##

--xYzZY
Content-Disposition: form-data; name="file1"; filename="testfile "
Content-Type: application/octet-stream
Test File Contents

--xYzZY
Content-Disposition: form-data; name="file4"


--xYzZY
Content-Disposition: form-data; name="file5"