Linking to xls

[GM]

I have set up a new table with one of the fields called "Roll no"
(This corresponds to a field in an excel file).

I set up the properties to long integer as I need to set up a
relationship with the same field in another table.

When I import the data as link from the excel file, it changes the
property of "Roll no" from Long Integer to text. Access does not allow
me to alter this - stating it is a linked file and properties can't be
changed.

Any ideas on what I'm doing wrong?

Gary