vMA does not provide any utilities nor is it meant to do backups, here is an article on what vMA is: http://www.virtuallyghetto.com/p/vmware-vma-vima.html
If you've read the above article, you'll realize that vMA is a VMware management appliance that has some CLI utilities that can be used to develop a backup solution using the vSphere API. One such script is which leverages the vSphere API to perform backups of VMs, please refer to the documentation for more details and ensure that you are NOT using the free licensed version of ESXi as that is not suppported with the script.
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William Lam
VMware vExpert 2009,2010
VMware scripts and resources at:
Twitter: @lamw
Getting Started with the vMA (tips/tricks)
Getting Started with the vSphere SDK for Perl
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