• Exchange oem.tgz on root of ESXi 3.5 Install CD with new oem.tgz
• Install with CD with OEM Community Version or IC8 oem.tgz  (SATA on Normal Mode)
• Boot from Knoppix 5.1, copy OEM.tz onto hda5 / Hypervisor Partition  (SATA on  Legacy Mode)
• Boot, works!

Hints:

• Use UltraISO und BurnISO to modificiate / burn the stock ISO
• http://www.vm-help.com/esx/esx3i/customize_oem_tgz.php