how to answer and end call on vvx 400 using Telephone Integration URIs

i am developing an app for a client who has the  vvx 400 phones running 5.2.0.8330 - and yes i've read the forum and will make sure that the client upgrades to 5.5.0 or whatever version they need to have

how to

1 answerc all on vvx 400 using curl - i assume this means Telephone Integration URIs

2 end call on vvx 400  using curl - i assume this means using Telephone Integration URIs

1. answer

i found:

http://community.polycom.com/t5/Polycom-Endpoints-Forum/FAQ-Can-I-remotely-control-the-Phone-or-send-content-to-the/td-p/28596

which provides example on how to answer with curl:

curl --digest -u Push:Push -d "<PolycomIPPhone>Key:Softkey1</PolycomIPPhone>" --header "Content-Type: application/x-com-polycom-spipx" http://10.252.75.219/push

BUT this is using a SOFTKEY!

and the docs here:

http://support.polycom.com/global/documents/support/user/products/voice/Web_Applications_Developer_Guide_5_0.pdf

say:

The programmable soft key related URIs are not supported on the browser on the Polycom VVX phones.

2. end call

I can't find any docs on how to end calls with curl