I havn't but it should be possible, you will need to make sure your tiles are coming from https as well.
In fact everything should be under https or else you will have issues.
You will need to modify the Virtual Earth provider (assuming your using Bing?) to use the https version of the WCF services, these should give you a https prefix. My understanding is this will only work with a production account. Also my caching to isolated
storage of this url may need to be checked to make sure it isn't caching the non https version.
For a really simple test it maybe worth setting up a really simple tile provider that just hard codes the Bing https tiles? this way you can prove it all works before dealing with requesting the token, using the https WCF service to get the path etc.
Please let us know how you go with it.