Omar - Can you give more detail via an example stated as a problem? It is likely that SUBSET functions can be used instead of pivot tables to define the transformed results at the intersections of specific values of specific fields.

SUBSET 'clauses' result in a data subset for use in other functions (such as SUBSET_MEAN or RANK). SUBSET 'clauses' are used to identify records by one constraint (e.g. Month is "February"). To identify records by multiple constraints, or use more complex logic, combine SUBSET with INTERSECTION, UNION and INVERSE (e.g. All of records in [Month is "February"] and [Client is "Acme Bank"]).

More detail on using SUBSET functions is here:

http://www.visokio.com/kb/subset-functions

As well as exploring tjbate's alternative suggestion above, please could you give a real-world example of what you want to do with formulas in the Pivot view? What kind of data, what fields, what Pivot configuration, and what formula? Post a sample IOK if it helps.