Excel interop adds @ sign to formulas

Hi,

when creating a spreadsheet using Excel interop's and VB.NET I need to add a formula to a cell.

for example the filter formula. I add it as =Filter but when it appears on the spreadsheet it appears as =@Filter

this means that only the cell that I added the formula to will bring back the data in the filter, whereas without the @ it would bring back the array in the corresponding cells.

is there a way of stopping the @ symbol appearing?

Thanks

Gareth