JP,
Perhaps you could provide some more details on your use case, as this may help with thinking up a more robust work around for you.
Do you intend to send to multiple devices over the lifetime of your application? How many? What's known about these devices? Will they always be the same or possibly changing (devices added, removed from the network)?
I'm wondering if we can do the ping on an initial communication step, extrapolating the MAC address somehow and adding a static ARP entry. Then subsequent sends to a particular host would be found in the ARP table.
But knowing more about your use cases may bring better insights and ideas to the table.
Steve