PowerVM Express and IVM limitations

When using PowerVM Express and IVM (no HMC) on a Power6 P520 , can I configure 2 LPARs in addition to a VIO server, or does the VIO Server count as one of the two LPAR's that PowerVM Express allows?

Google for - PowerVM Express
second hit:
IBM Power Systems PowerVM Express Edition

"Features:Micro-Partitioning Support: Create up to three partitions per server of a minimum granularity of 1/10th of a CPU and a maximum of the entire server. Dynamically move processors and resources from one partition to another with no application downtime."

If you could only have two partitions and one was a IVM / VIOS, what would be the point in allowing (or paying for) IVM / VIOS?