Converting VMs from hyper -V 2012 host machine to vSphere ESXi 5.1 host machine

I want to convert the Hyper-V 2012 hosted VMs to ESXi 5.1 host machines using VMware Converter 5.1.0 build -1087880 but it prompt below error message when i try to connect the Hyper-V 2012 host machine using "Hyper-V" Server option in source of VMware converter utility.

" The version of the selected Microsoft Hyper-V is not supported. Select an earlier version of Microsoft hyper-V server or another supported source type."

Note:- All VMs are created with VHDx disks.

Please help out that what method should be used for converting these VMs. snapshot of error is also attached with this post for reference.