Accessing Excel s/sheet from servlet

Environment:  JBuilder4, Servlet driven Web app, excel spreadsheet w/macros

     I need to get data from the user via servlet, send that data to an excel spreadsheet on separate server, where it executes some business logic and calculations and returns calculated data to the servlet.  The company I am developing this for insist that the business logic remain on a spreadsheet on a separate server, so I can't do the sensible thing and calculate it within my Java App.  The spreadsheet contains macros within the xls files.  I found some great tools called Formula1 that *almost* do the job, but they can't handle the macros.
     Currently I am getting the data from the servlet, dumping it into a textfile on the remote server, then calling a batch file on the server to start excel and load the data into the spreadsheet, which calculates stuff and dumps the relevant data into another textfile, which I then read:

public static CalcResult getCalc(CalcRequest pCalcRequest)
{
   try
      {
         writeFile(pQuoteRequest);//here I write to textfile on remote server
         Process proc = Runtime.getRuntime().exec("cmd /c c:\\calcserver\\gocalc.bat");//run bat file to load from txtfile into spreadsheet
         //capture output in a stream
         proc.waitFor();  //wait for the process to finish
         CalcResult oCalcResult = XLreader.ReadResults();//reads from txtfile with new calculated data
         oCalcResult.setName("test");//populate Calcresult.
         return (oCalcResult);
      }
   catch{...}
}
     Is there a better, more scalable solution?  Thinking of embedding xlspreadsheet into a vb app, then do some kind of OLE, COM, or CORBA mojo (new to me).  Also, this spreadsheet will be handling many requests, so maybe I should create many xl objects?  Need an Enterprise scale solution, any help appreciated!