Thanks Michael. That will probably work but I just tried doing it with a Generic Handler and it worked. This is what I did: (hope it helps somebody)

 Generic Handler file:

public class pdf : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            using (var ctx = Components.Data.Model.DecisionReportModel.Instance())
            {
                int docID = Convert.ToInt32(context.Request.QueryString["docID"]);
                int langID = Convert.ToInt32(context.Request.QueryString["lang"]);

                DocumentLanguage doc = null;
                List docs = ctx.DocumentLanguages.Include("Document").Where(dd => dd.DocumentID == docID).ToList();
                if (docs.Find(d => d.LanguageID == langID) != null)
                {
                    doc = docs.Find(d => d.LanguageID == langID);
                }
                else if (docs.Find(d => d.LanguageID == 1) != null) //default to English
                {
                    doc = docs.Find(d => d.LanguageID == 1);
                }
                else if (docs.Find(d => d.LanguageID == 2) != null) //French
                {
                    doc = docs.Find(d => d.LanguageID == 2);
                }

                if (doc != null)
                {
                    string strFileName = doc.Document.FileName;
                    context.Response.ContentType = "application/pdf";
                    context.Response.BinaryWrite(doc.FileContent);
                    context.Response.AddHeader("Content-Disposition", "attachment; filename=" + strFileName.ToString());
                }
            }
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }

...and I call it from my repeater's ItemDataBound like this:

lnkPDF.NavigateUrl = "pdf.ashx?docID=" + d.DocumentID + "&lang=" + l.LanguageCultureID; 

Thanks

P.S. I Like the web service idea though!