How to align text in table and specify column width??

Hi All,

How can I align text(top,center,bottom)  in table ??? 

I am using TableCellF() function...in this function, parameter for text alignment is not available.

and also I want to set the width of table column...by default the table width divided equally into no. of column...

suppose I have a table width 100 I want to create two column in row...in which one column width should be 20% of table width and second column width should be 80%

how can I achieve this ??

Any help with regards to above mentioned difficulties will be highly awaited and much helpful.