Error creating Vm with custom source image and custom vhd storage location

Hi all,

I have created different VMs without problems using the azure template of vm with custom image, but when I looked where the VM creates the VHD I saw it was saved on the storage where the custom image is located. Looking the api (sdk-for-net) I saw that actually I could define where the image can be (I tested too), but when I use these sequence I am getting Error:

```

"storageProfile": {
"osDisk": {
"name": "vmssosdisk",
"caching": "ReadOnly",
"createOption": "FromImage",
"image": {
"uri": "[parameters('sourceImageVhdUri')]"
},
"vhd": {
"uri": "[concat('https://', variables('differentStorageAccountName'),'.blob.core.windows.net/oshardos.vhd')]"
}
}
}
```

### Error

```
{
"status": "Failed",
"error": {
"code": "DeploymentFailed",
"message": "At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/arm-debug for usage details.",
"details": [
{
"code": "BadRequest",
"message": "{\r\n \"error\": {\r\n \"code\": \"InvalidParameter\",\r\n \"target\": \"osDisk.vhd\",\r\n \"message\": \"Parameter 'osDisk.vhd' is not allowed.\"\r\n }\r\n}"
}
]
}
}
```
**Parameter 'osDisk.vhd' is not allowed.**

Is there some way how I could define where the VM store the vhd?

Thanks

Start with the Azure VM template and the storageProfile.osDisk configuration shown in the report; trace how the custom image and VHD fields are handled during deployment. Reproduce the InvalidParameter response and determine whether the template supports a separate VHD location, then document the confirmed behavior or required change.

Written by the indexing model from the issue text.