I am working on building our first ESXi 5.1 image for our HP Blade servers as well. We'll utlimately be using Stateless Caching via Auto Deploy, but my initial testing will focus on doing a statefull install.
One thing I can tell you from my research so far. AMS is for Gen8 hardware only. It's the "HP Agentless Management Service for ProLiant Gen8." It looks like you're running on a BL460c G7.
Most likely the hp-ams component is stalling because it's trying to talk to the "embedded agents" and eventually times out. If you're not deploying to any Gen8 hardware, just remove it from your image.
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c03510875/c03510875.pdf -- "Starting with HP SIM 7.0, embedded agents
along with HP Agentless Management (HP AMS) provide the default management software option installed on HP ProLiant Gen8 servers from HP Service Pack for ProLiant."
As to why you cannot control the server via the iLO, make sure in the BIOS you didn't disable "Legacy USB Support" (System Options -> USB Options -> USB Control.) We have this setting to "External USB Ports Disabled" to enable iLO control, but disable the ability to plug any USB device/key into the blade itself.
I'll let you know how things go once I build my first image and install it on a BL460c G7. I am building on the SPP 2012.10.00 release:
http://vibsdepot.hp.com/hpq/recipes/October2012VMwareRecipe3.0.pdf
Note: From what I can tell reviewing the release notes for the SPP release, SPP 2012.08.00 is the first firmware release set from which HP officially started supporting ESXi 5.1.