Using Generic <T> to create a function for generating an array from a GH_Structure

I asked this question in this thread:

http://www.grasshopper3d.com/forum/topics/creating-an-array-in?id=2...

but I thought perhaps this was the relevant place to put it instead.

I was attempting to replicate the function that David wrote for converting an array into a datatree by nested for loops:

public DataTree<T> Array2Tree<T>(T[,] arr) {      
//Declare a new DataTree   
DataTree<T> tree = new DataTree<T>();  
//Iterate over the first dimension of the array    
for (Int32 i = 0; i <= arr.GetUpperBound(0); i++) {             
//Iterate over the second dimension of the array           
for (Int32 j = 0; j <= arr.GetUpperBound(1); j++) {                     
//Insert the current value into the DataTree.                      
//The first dimension ends up as the Path,                         
//the second dimension ends up as the index.                       
tree.Insert(arr[i, j], new GH_Path(i), j);                 
}  
}  
return tree; 
}

I am using GH_Structure (because I'm making a custom component) instead of DataTree using the generic type <T>, but it gives me the following error in Visual Studio:

"The type 'T' cannot be used as type parameter 'T' in the generic type or method 'Grasshopper.Kernel.Data.GH_Structure<T>'.  There is no boxing or type conversion from 'T' to 'Grasshopper.Kernel.Types.IGH_Goo'."

It seems to work the other way round, if I create a function that reads a GH_Structure and creates a corresponding 2d array with a corresponding list of addresses:

public void convertStructureToArray<T>(GH_Structure<T> inStructure, out T[][] outArray, out List<int> outAddress)
{
List<int> pAddress = new List<int>();
int pathCount = inStructure.PathCount;
T[][] ghArray = new T[pathCount][];
for (Int32 j = 0; j <= inStructure.PathCount - 1; j++)
{
GH_Path a = inStructure.get_Path(j);
String b = a.ToString(true);
char[] c = b.ToCharArray(0, a.Length);

foreach (char ch in c)
{
pAddress.Add(int.Parse(ch.ToString()));

}

IList<T> branch = (IList<T>)inStructure.get_Branch(j);
for (Int32 i = 0; i <= branch.Count - 1; i++)
{
T goo = (T)branch[i];
ghArray[j][i] = goo;
}

}

outAddress = pAddress;
outArray = ghArray;

}

Is there anything I can do to get around this?  It would make it a great deal easier not to have to make a new function for each type of GH variable that the function could possible have to process...

Any help would be greatly appreciated.