Daml sandbox doesn't allow setting System properties

Hi there, I have tried setting System properties as follows when launching the sandbox (SDK 2.6.0)

daml sandbox  --config sandbox.conf --bootstrap sandbox.canton -DmyProp=foo

However I get the following error:

Error: Unknown option -DmyProp=foo

According to the help message this way of setting properties is supported.

If you’re setting your own config file you’re probably better off using the canton jar directly with java -jar, which definitely does 100% support -D to set properties.