PSx ModCD- how to switch to disc 2 ????

[KDM]

I have a ModCD (bootcd). For example when playing Metal gear solid, when its is time to switch to disc two I cant, even if i try to use the modcd first again. I even have played around with the lid utilly that fools the station to think the lid is down. In short

Anyone know how to play a 2 or more disc game using a ModCD??