Creating a Customer File to Download

I'm trying to add an XML file for a customer to download. I can create the "File" object, and I can't seem to attach it to the CustomerDownload for the customer.

Here is my sample code.

 //add license file  File file = new File();  string xmlLicense = "<xml />";  System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();  file.content = encoding.GetBytes(xmlLicense);  file.fileType = MediaType._XMLDOC;  file.name = string.Format("License File For {0}", cust.companyName);    CustomerDownloadList dlList = new CustomerDownloadList();  CustomerDownload[] dl = new CustomerDownload[1];  //dl[0].file = file;  dlList.download = dl;  cust.downloadList = dlList; 

the problem is on this line.

//dl[0].file = file;