OLAP Calculated column using Special Categories

[ceosp]

Hi!

Anyone knows how to create a calculated columns using Special Categories? Ex.:


<measure>  | <last month> | <current month> | <current month-last month>
-------------------------------------------------------------------------------
<member1> | <value11>     | <value12>       | <value12 - value11>
<member2> | <value21>     | <value22>       | <value22 - value21>
<...>


How do I calculate <current month-last month>?

Thanks, Carlos

[japwah]

Create a calculated member with the expression

<current month> - <last month>