iscsi with gpxe (windows 7) - not booting

Hi All,

I am trying to boot via iscsi from my Readynas Pro 6 via gPXE, my fw on readynas is 4.2.21

I'm seeing this issue when i open the syslog on the nas:
Aug 11 14:27:39 KDNAS kernel: No response for proposed key "ImmediateData".
Aug 11 14:27:39 KDNAS last message repeated 5 times
Aug 11 14:27:39 KDNAS kernel: MAX_LOGIN_PDUS count reached.
Aug 11 14:27:39 KDNAS kernel: iSCSI Login negotiation failed.

I can mount iscsi luns no problem from my desktop / laptops to the readynas..

The ietd.conf from the readynas is as below:

Target iqn.2012-08.KDNAS:esx4i
Lun 0 Path=/c/.iscsi/esx4i~0,Type=fileio,ScsiSN=RN20BRG00224-002,IOMode=wb
# desc esx4i 0 esx4i
HeaderDigest CRC32,None
DataDigest CRC32,None

my script for gpxe is as follows:

#!gpxe
ifopen net0
set net0/ip 10.10.8.253
set net0/netmask 255.255.255.0
set net0/gateway 10.10.8.1
set net0/dns 10.10.8.1
set keep-san 1
sanboot iscsi:10.10.8.99::3260:0:iqn.2012-08.KDNAS:esx4i

when gpxe boots from my usb, I get the message "could not initialise ISCSI device" and the logs as per above are seen in syslog on the nas..

I've researched this to a similar issue users had on a qnap device here:
http://forum.qnap.com/viewtopic.php?p=129084

Now, i'm not really a huge linux guru and looking at this post, i've got to go build a linux vm (i don't have one currently), download a load of packages and frig about with an iscsi.c file and recompile for gpxe..

has anyone come across this issue on their readynas? if anyone has a way for sorting this out without doing the recompile of this file i would really appreciate it.. or failing that, explain in english without the assumed linux knowledge from a scratch vanilla build of ubuntu so i can sort it out myself..

thanks guys,

K