As it seems on official site it doesn't supported for version 6.0 of portal.
But is there any possibility to use 64 bit jvm and 64 bit portal?
A:
Yes but you are better off with Portal 6.1.0.1 and Was 7. In Portal 6 and WAS 6 the 64-bit JVM the same app can have a much higher memory footprint than the 32-bit JVM. This issue is addressed by the combination of Portal 6.1.0.1 and WAS 7.
You will want to take a look at this page: IBM - WebSphere Portal detailed system requirements http://bit.ly/bfUbbB
Once there, drill down to the platform and version of interest.
T.Rob
2010-05-23 20:31:52