Originally Posted by Right Way Up
Straight from the FCTM:
"If selected speed is to be used to comply with ATC, the requested speed should
be selected on FCU. A speed below the manoeuvring speed of the present
configuration may be selected provided it is above VLS."
FCTM & the Instructor Support Manual states similar.
The FCTM is highly recommended reading- for old Boeing boffins especially!