SendKeys Ctrl-PgDn to Java app

Hi,

We have a Java app at work (running on Windows 2000) and I'm trying to use
SendKeys in Microsoft Access VBA to get it to do a Ctrl-PgDn. The Java app
is respoding to a single key. For example, this works:

AppActivate "Java app"
SendKeys "{F10}", True

However, a combination key such as Ctrl-PgDn does not work

AppActivate "Java app"
SendKeys "^{PGDN}", True

Please note that when I go to the Java app itself and type in Ctrl-PgDn from
the keyboard, everything works fine.

Any ideas on why this might be happening? Does any one know of any
work-arounds?

Thanks,
Alistair