What are you trying to Transfer?
As I recall, when you have the setting of "SYNC DATA" or "SYNC MUSIC", that refers to an application that you have pre-installed ... e.g., RHAPSODY ... Just by plugging the phone in you will not see it like another folder or USB device - and this is true even if you DO have another Memory card.
If you install another Memory card you can access the folders on that card by REMOVING the card and then use a Micro SD Card reader (most newer laptops have them, or you would need to buy a reader.) With this approach you can manually copy Music & Pics, etc.. directly to the Card, remove it from the Reader and put it back into your
Dare to use the files you copied.
The last option is to download and install BitPim. When launched, that application will see everything on your DARE.
I would personally recommend that you just buy an 8GB Micro SD card... They're not that expensive and make copying your Music/Pics back and forth very very simple. YMMV.