I am writing some Apex code to implement my own version of Email-to-Case.

Using the API Developer's Guide information about the fields in the EmailMessage standard object, I was able to include the following code for creating a new EmailMessage in my handleInboundEmail method.  However, the API documentation does not specify any attachment fields aside from the boolean HasAttachment.  Is there a way I can add email.binaryAttachments and email.textAttachments to the new EmailMessage object?

    ...

    // new EmailMessage object to be created
    EmailMessage[] newEmail = new EmailMessage[0];

    // Lookup case based on the case number
    try
    {
      Case vCase = [Select Id, CaseNumber, ContactId, OwnerId
        From Case Where CaseNumber = :myCaseNumber Limit 1];
        
        String ownerIdStr = vCase.OwnerId;
        System.debug('Owner ID as a string = ' + OwnerIdStr);

        
        newEmail.add(new EmailMessage(
            FromAddress = email.fromAddress,
            FromName = email.fromName,
            Incoming = true,
            MessageDate = System.now(),
            ParentId = vCase.Id,
            Status = '0',
            Subject = email.subject,
            TextBody = email.plainTextBody,
            ToAddress = email.toAddresses[0]));

        // Insert the new EmailMessage into the case
        insert newEmail;
      }

      ...

I need to create a "Reply" button for a Task Detail Page that allows a user to reply to a case task when its status is Inbound Email.  I am trying to pass parameters to the EmailAuthor.jsp URL, as suggested in the Quick Email Button Salesforce blog, so that clicking on the "Reply" button brings a user to the Send Email page with the Task's Comments already in the email body.  I tried creating an email template with {!Task.Description} in the body, but email templates cannot access Task fields.  I am currently trying to change the body of the email through the parameters, like so:

location.replace("_ui/core/email/author/EmailAuthor?retURL=/{!Case.Id}&p3_lkid={!Task.What}&rtype=003&p2_lkid={!Case.ContactId}&p6=Re:
{!Task.Subject}&p7={!Task.Description}");

However, {!Task.Description} is too long to fit into the URL, and I get the following error message: "A problem with the OnClick JavaScript for this button or link was encountered: unterminated string literal."  Does anyone have any suggestions for how I can get around this?