[otrs] Migrating to 2.3.4

Hi, We have just recently installed OTRS 2.3.4 on SUN Solaris 10 and this instance is running fine. Now we want to migrate our old queues from OTRS 1.2.3 (on Solaris 10) to new installation. Can someone help me getting started as I am finding kind of stranded at the moment. Your help is greatly appreciated. Thanks.