Greetings. This is a simple and straightforward question, and I believe the answer shouldn't be too difficult. Here is my setup and what I am trying to do.

Soundcard #1 is on my PC. It is a cheap soundcard, and it's where all my MIDI commands originate. I am sending MIDI commands starting at Soundcard #1.

KR-277 is my digital piano.

Soundcard #2 is my professional recording soundcard. I want everything to be received here.

I have my Soundcard #1 MIDI Out hooked up into my Piano's MIDI In. The connection works, because when I send MIDI commands from the PC, the piano plays it.

I have my Piano's MIDI Out to my MIDI In on Soundcard #2. This also works, because when I play keys, the commands are sent successfully to Soundcard #2.

Now, the problem, is that when I send commands from Soundcard #1, the MIDI commands don't make it to Soundcard #2. The piano plays them, but the MIDI commands aren't going through the piano into it's MIDI out. They are simply played. Now, my piano doesn't have a MIDI THRU port, but I think that's okay.

Is there anyway to get my piano to use it's MIDI Out port with all the data it receives from it's MIDI In port? As you see, I am just daisy chaining to get to Soundcard #2. The manual had no information on sending MIDI information it receives via MIDI in.

What you need is a MIDI THRU port.

MIDI OUT is like a "mouth". All it does is send messages.
MIDI IN is like an "ear". All it does is receive messages.
MIDI THRU takes what it hears and passes it on (kind of like a "gossip"). Used for daisy-chaining MIDI devices.

The correct connection in your case would be:
Soundcard #1 MIDI OUT to Digital Piano MIDI IN
Digital Piano MIDI THRU to Soundcard #2 MIDI IN

I'm not familiar with your specific digital piano. Some electronic instruments allow you to switch your MIDI OUT port to a MIDI THRU port electronically. Check your owners manual as to whether your keyboard can do this. If not, you might consider a MIDI THRU box such as this one:
http://www.bhphotovideo.com/bnh/controller/home?A=details&Q=&is=REG&O=productlist&sku=189906

Hope that helps.