yes, you can.
Write-down your own TEncodePlugin for encode/decode.
Than use it in your application (probably compiled into your code).

For VTDbManager you must have dll, which will export some functions (see sources of Asphyre, it is clear) and say to VTDBMan, that you want to use it (from cmd line or xml).

Little problem is, that VTdbManager now doesn't support sending parameters to plugins, so your password must be always same.

In future version i'll add this.