ITSCM and BCM should be integrated. BCM is driving ITSCM in a way that BCM defines objectives (from the business point of view). Since all business activities are usually supported by IT services – defined BCM targets directly influence ITSCM targets.
In practice, ITSCM people should talk to BCM and get inputs for their TSCM objectives. If BCM doesn't exist, ITSCM should speak directly with the business.