Why isn't KeyRemap4MacBook's "PageUp/PageDown to Left/Right (only in iPhoto)" setting working?
I posted my question on the KeyRemap4MacBook Google Group, and got a reply from Takayama Fumihiko, the creator of KeyRemap4MacBook.  He had me send him the vendor ID and product ID for the device, and sent me back a private.xml file with a new setting that worked.  (The pre-defined "PageUp/PageDown to Left/Right (only in iPhoto)" setting only works with the vendor ID and product ID for the Kensington K33374 USB remote.)

Here's the private.xml file contents:

&lt;?xml version="1.0"?&gt;
&lt;root&gt;

  &lt;devicevendordef&gt;
    &lt;vendorname&gt;Tenx_Technology_Inc&lt;/vendorname&gt;
    &lt;vendorid&gt;0x1130&lt;/vendorid&gt;
  &lt;/devicevendordef&gt;

  &lt;deviceproductdef&gt;
    &lt;productname&gt;Tenx_wireless_USB_gadget&lt;/productname&gt;
    &lt;productid&gt;0x6604&lt;/productid&gt;
  &lt;/deviceproductdef&gt;

  &lt;item&gt;
    &lt;name&gt;PageUp/PageDown to Left/Right (only in iPhoto)&lt;/name&gt;
    &lt;appendix&gt;(This is effective only with "Tenx_wireless_USB_gadget")&lt;/appendix&gt;
    &lt;identifier&gt;private.pageupdown2leftright_iphoto&lt;/identifier&gt;
    &lt;only&gt;IPHOTO&lt;/only&gt;
    &lt;device_only&gt;DeviceVendor::Tenx_Technology_Inc,DeviceProduct::Tenx_wireless_USB_gadget&lt;/device_only&gt;
    &lt;autogen&gt;--KeyToKey-- FROMKEYCODE_PAGEUP,   KeyCode::CURSOR_LEFT&lt;/autogen&gt;
    &lt;autogen&gt;--KeyToKey-- FROMKEYCODE_PAGEDOWN, KeyCode::CURSOR_RIGHT&lt;/autogen&gt;
  &lt;/item&gt;

&lt;/root&gt;


See the "How to add new settings" section in the KeyRemap4MacBook documentation for instructions on what to do with the private.xml file (except replace the file instead of editing the original one with a text editor).