ResolutionParallels Server for Mac 4.0 (PSfM) does not allow to manage Virtual Machines from iPhone. This limitation can be worked around by using Parallels Virtual Automation (PVA).
PVA is web-based control panel which can be used in Safari on iPhone or iPad. Using PVA you have full control over your VMs from iPhone or iPad. You can start or stop VMs, install Tools, see resources usage, migrate, create backups etc. Parallels Server for Mac license includes PVA support.
Refer to the following articles for how to install PVA on PSfM server:
Installing Parallels Virtual Automation Automatically
Installing Parallels Virtual Automation Manually
Setting Up the Management Node Manually
Note there are two limitations of this solution:
1. "VM Remote Console" feature of PVA is not available on iPhone and iPad. This functionality requires Java that is not supported by iPhone and iPad.
2. PVA does not work with NAT without an additional configuration.