How to summarize a text filed ?

Greetz!

I need to perform a SUM on a text field in CR 8.0. I tried creating a formula filed which contained something like this: SUM {textfield.text} but the report said: Unknown filed name. Now, the text field ( crystal reports text object actually ) is not a database field, but a plain text box which contains certain data. Can this be achieved at all ? Summarizing or any other function over a text box ?

Thnx.Hi

It is not possible to use SUM () for a non database field.|||Ok. Well, is there an alternative ? This text box mentioned earlier contains a vital data which I collected from a foreign source (used a text driver in VB to read it from a text delimited file ), and I can display it's value in a details section, but as I said earlier, I cannot SUM it. So .. if there's an alternative approach using crystal, I'd more then appritiate it.