I got it working by querying the database and getting the attribute keys.
Here's the working file.
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<AdapterKinds>
<AdapterKind adapterKindKey="VMWARE">
<ResourceKind resourceKindKey="DATASTORE">
<Metric attrkeyId="4371" label="Commands Per Second" />
<Metric attrkeyId="4387" label="Disk Command Latency (ms)"></Metric>
<Metric attrkeyId="4390" label="Usage Average(KBps)" />
<Metric attrkeyId="4369" label="Commands Issued" />
<Metric attrkeyId="4372" label="Physical Device Command Latency (ms)"></Metric>
</ResourceKind>
</AdapterKind>
</AdapterKinds>
Thanks!