Passing object by ref to COM not working

Guys,

Newbee just getting into C# needs to help:

I'm trying to call a dll functions which looks like this:

public double[,] Correl(string action, ref object returns, double observation_frequency);

Issue is in second argument, which seems to require  data type like {Int32 UBound(System.Array, Int32)}

My call looks like this:

Double[] vect1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };// {{ 1, 2, 3, 4, 5, 6, 7, 8, 9 },{ 1, 2, 3, 4, 5, 6, 7, 8, 9 }};
object oncloses = vect1;
nFullMatrix = Correl.Correl((string)"AVC",ref oncloses, (double)frequency); 

When for testing I call with onedimensional array I get error: Argument 'Rank' is not valid for the array. Know that it requires two dimensions, but at least values seem to pass and something happens :-)

When I call with twodimensional array like below, I get error: Parametername: Argument 'Array' is Nothing.

Double[,] vect1 = {{ 1, 2, 3, 4, 5, 6, 7, 8, 9 },{ 1, 2, 3, 4, 5, 6, 7, 8, 9 }};

I was using this from VBA/Excel quite a lot without any issue, using type universal Variant, but seems C# is a bit more picky..

Spent my afternoon online looking for the trick, please tell me it's really tricky not to get frustrated..

Thanks in advance,

Alex