現在対応中ですので、もう少しお待ちください。

Excite翻訳: Please wait a little more while corresponding now.
@nifty翻訳: Since it is under correspondence now, please wait a little longer.
Babel Fish: Because presently it is in the midst of corresponding, already please wait a little.
Google翻訳: Is currently available, so please wait a little more.
Yahoo!翻訳: Please wait a little more now because it is the whole correspondence.
OCN翻訳: It corresponds at present, so please wait a moment a little more.
Windows Live Translator: Currently corresponds in, a little more please wait.

Summary:
Except Google, all engines choose "correspond" or "correspondence" for "対応"
though these words have different meanings from the original Japanese word.
For the latter half, Excite, @nifty, Google, Yahoo give very similar and natural expressions.