Without getting my laptop and D710 out to look at I'd say look at menu 528 and look at your com port data speed.
1200 is not an option for that, yet you have your com Port set for 1200.
This is the baud rate for the computer to talk to the radio and is not related to the APRS data speed options.
I'd recommend 19200, but whatever you choose they have to be the same.
Let me know how you make out with adjusting menu 528 and adjusting your com port speed. If you still can't get it I'll get my laptop out and send you some screenshots along with radio menu settings.
From: Don Poaps va7dgp@... [aprsisce]
Sent: Sunday, April 22, 06:07
Subject: Re: [aprsisce] Kenwood TM-D70 does not talk to APRSIS
I should say Com 5, 9600 baud with the RT System plug. If using Simply Kiss, the Radio should go into Packet 12.
New Westminster, BC