SSRS 2012/SharePoint 2010 Integrating Mode How to set the MaxHttpCollectionKeys for parameters in a report.

From what I understand there is a default max setting for the number of items in a single parameter for an SSRS report. Does anyone know the powershell command to change that default setting? It looks like in SSRS 2008 it was the MaxHttpCollectionKeys in the reportserver.config. Howerver in 2012 with SharePoint Integration it looks like you need to use powershell (Get-SPRSServiceApplication, Set-SPRSExtension...).

Anyone know how to change that setting to allow more items in the collection?