Create a Crosstab column using NON aggregated column value

[MegaCogman]

I am trying create a new column on my crosstab report which uses the aggregated measure and a value from a non aggregated column.  below you will see that I have measures accumulated for a 12 month period... then I have and ave of those 12 month in a column.   For My new column I want to multiply the average value of 5.1 by the Non Aggregated Price column  5.30 ?    every thing I have tried keeps giving me an error that price cannot be used in the calculation.  I have tried using a query calculation as well as Cross tab with measure to do the calculation.   

non agg.                                          aggregated measure

Price                          Jan  Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec      Ave     New col
  5.30                          2     3     3    3     4    5    6    6    6    6     7     7         5.1

Any Suggestions would be greatly appreciated

[CognosPaul]

What is the error exactly, and is this a relational or dimensional data source?

[MegaCogman]

Thanks for the reply.   I am using Relational data source. 

When I add a query calculation and choose other ... I create a data item which I then add the calculation for Ave *  Price. 

I get the error    Measure valueSet="Total Value" can not have another measure as an attribute: groupBody="Purchase Pack Size0".