Ummmm think the haynes states that 'it is possible to change the cambelt with the engine in situ, however the easyest option is to remove the engine'................or something allong those lines. pLease bare in mind i'm not 100% that the ps pump is ran from the c/belt, but preety sure.
Best advise is to buy a haynes and have a good read.
Also is the Valver new to you, or you had it a while?????
Reason being lots of people think they need replacing because of the noise & 9/10 times this is normal, I know mine and three other mates valvers are realy noisey, but function fine.