local SQL: memo field update problem

It seems that I can't update a memo field in a local paradox table
using TUpdateSQL (or an SQL UPDATE statement in the database
desktop). BDE just yields a 'type mismatch' error.
Is there a workaround or am I missing something ?

Here's an example: Let customers be a paradox table having
an integer field CustID and a memo field (MyMemo).
Assume a record with CustID = 1 exists. Issuing a

UPDATE customers SET MyMemo = 'test' WHERE CustID = 1

command in a SQL window of the Database Desktop yields a
'type mismatch' error. Should I cast 'test' to a memo type ? If so
how is it done ?