Question: Custom defined functions not working in Matrix entries

My question is a bit vague, but I hope someone can point me in the correct direction for a solution anyway. A Maple Package was been defined and placed in the Lib folder in Maple 16. The package does contain a number of custom defined functions, say Cos(v) and Sin(v) - with a capital letter to distinguish them from the usual built-in functions in Maple. After having called the package using the with statement, the new function works well in the worksheet. It also works well when the functions are being used in vectors using the < and > symbols. So <Cos(v),Sin(v)> is working. However if I choose the Matrix Palette creating a 2 times 1 matrix (2 rows, 1 column) a Matrix with square brackets is being displayed. But now the functions are not recogniced. Why? Can somebody give be a suggestion to what can be the problem and how it can be repaired in the package?

Regards

Erik