Question on promotable locks

Hi, after getting a promotable lock on a row, are other processes able to set NEW shared locks? This would be strange, as I thought that the promotable lock will announce my intend to do an upddate. If other processed can set new shared locks, I will - perhapes - newver promote my lock to an exlusive lock. The ANSI intention exclusive lock will behave like this. Anyone knows how it works? Thank you, Jens