Creating HMAC Hash

After a couple fruitless hours of trying I need some help...  I'm trying to sign a URL for a REST API and, for the life of me, can't get CF to output the expected result.  The API is Aspose and the the instructions are here:

http://www.aspose.com/docs/display/totalcloud/Request+Format

According to their example I need to hash this URL: http://api.aspose.com/1.1/storage/folder/test_folder?appSID=c821f123-1a8b-4b97-925a-9d69a6b2fcd8

Using this Key: 23e9d89a967a5f18142221fa8f7cbcd0

And the result should be:Z98TBrlwdtx3pTa6fWVD/Q0c2dE=

According to the C# example they give the algorithm should be: HMACSHA1 and the encoding: UTF8

I cannot get CF to produce this result.

I've tried using the CF function hmac().

#toBase64(hmac(url,key,"HMACSHA1","UTF8"))# gives me: MjYwMkQxN0EyM0IyMzkxNjNDMDU4QTQyMjc3RDgyNkMyNzM0NTA3OA==

I've also tried suggestions and variations found here:

http://stackoverflow.com/questions/9186773/coldfusion-hmac-sha1-encryption

and Ban Nadel's Crypto.cfc.

What am I missing here?