hi Bhrami,
The DAM Flex API is only for retrieving data through data requests. The way to achieve what you're asking is the following:
1) Send data request for a custom property "availableDisksForVmfs" in your host view on the UI side
2) Create a PropertyProviderAdapter on the java side, like the vsphere-wssdk-provider sample
3) In that adapter, handle the query for property "availableDisksForVmfs" by calling the vSphere Web Service SDK and returned the data to the UI.