The changes to vCenter to enable linked clones have proven to be a considerable challange to the developers. I do however expect the update shortly now that Lab Manager 4 is out and fully supported on vSphere. both LAb Manager and View utilise Linked Clones in there provisioning engines.
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Tom Howarth VCP / vExpert
VMware Communities User Moderator
Blog: www.planetvm.net
Contributing author for the upcoming book "[VMware vSphere and Virtual Infrastructure Security: Securing ESX and the Virtual Environment|http://my.safaribooksonline.com/9780136083214]”. Currently available on roughcuts
Tom Howarth VCP / VCAP / vExpert
VMware Communities User Moderator
Blog: http://www.planetvm.net
Contributing author on VMware vSphere and Virtual Infrastructure Security: Securing ESX and the Virtual Environment
Contributing author on VCP VMware Certified Professional on VSphere 4 Study Guide: Exam VCP-410