Problem with VARCHAR > 255 chars in MSSQL 7.0.

I am connected to MSSQL using the BDE native driver.
My problem is: I have a description field that is stored  in the database as
VARCHAR(512)
Setting is not a problem but when i try and go to get the characters
from the database the whole string is truncated to 255 chars. i have tried
getting them AsString, Text and As Memo but they all truancate the string.
Any help with this problem would be greatly appreciated,
Una.