[Vala] how to declare multi-dimensional arrays in Genie?

[Ron Murawski <ron horizonchess com>]

 How to declare a global, uninitialized multi-dimensional array in Genie?
I'm using Vala 0.9.2

The following code does not work:

myarray : uint64[13,64]
error: syntax error, expected ']' but got ',' with previous integer literal

myarray : new uint64[13,64]
error: syntax error, expected ']' but got ',' with previous integer literal

myarray : array of uint64[13,64]
error: syntax error, no expression allowed between array brackets

myarray : new array of uint64[13,64]
error: syntax error, no expression allowed between array brackets

myarray : uint64[13][64]
error: syntax error, expected line end or semicolon but got '['

myarray : array of uint64[13][64]
error: syntax error, no expression allowed between array brackets

Thanks for any help,
Ron