I need to have a block to draw an array. I do not need a sophisticated cells merging, just rows and columns with resizing, adding a col or a row.

You can try to build the block yourself, there is plenty of examples of custom blocks in TMS Diagram: FlowchartBlocks.pas, ElectricBlocks,pas, UmlBlocks.pas, etc.. If I understood correctly your block would be rather simple, just a rectangle with several text cells?