Vötsch VCL 7010 - ASCII-2 interface protocol

Hi !
I have some troubles communicating with my Vötsch VCL 7010 climatic chamber.
I would like to control it via TCP/IP protocol in LabView, and here is the problem : I am sendind what seems to be the right strings of command, the chamber response is 0<CR> as it should be, and if I ask for a setpoint of 70°C I have a setpoint of 70°C.

But the oven doesn't want to start.

Here is exactly the string I send :
$01E 0050.0 0000.0 0000.0 0000.0 0000.0 0000.0 01000000000000000000000000000000 <CR>

Does anybody have any ideas on the subject, or is there anyone who is using this type of chamber and is able to communicate with it ?

Another odd thing : all my programs worked with the VT 4004, and the protocol is apparently the same...

Here is the datasheet :
http://forums.ni.com/ni/attachments/ni/140/44043/1/PROTOCOLE%20RS%20232.pdf