Centos 5 physical to virtual

Hi, Having problems converting a Centos 5 physical server to virtual, all methods tried clonezilla disk to image have only resulted in kernel panic and un-bootable. The kernel is old (2.6.18-8.el5) and a lot of newer technologies are not compatible. I am unable to make any changes to the physical machine as it is in production ( yeah i know right!), however i can schedule downtime to take images. My preference would be to create an image offline of the entire system and somehow create a virtual machine from image. Also note I have tried Vmware converter and that resulted in a VM that would not boot. I know I dont have a lot of detail here, so please tell me what i need to tell you to enable you to help me. I am looking for the simplest method to get this physical machine to virtual without upgrading Kernel or installing 3rd party apps.