Just googling on the web, it looks like you can't. It seems you need the Flex builder. I was trying to avoid the fully GUI tool. Is there a way to bypass this?
The charting components are part of Flex Builder Professional. If you have the charting swc's, you can use the charts without Flex Builder though. You'll need to have a valid license in order to get rid of the watermark.
The latest Flex SDK is 3.2 and no, they don't include the charting components. You need a license for Flex Builder 3 Professional which includes the charting components.
If you already have this and need to move to a new version of the SDK for your project then you need to manually copy the charting component swcs into the new SDK folder. Just did a search for the instructions to do this:
If your application uses Flex Builder Professional features such as data visualization components or automated testing, you will need to copy those elements from the latest milestone SDK that came with Flex Builder into your newly downloaded SDK. The relevant files that you need to copy are:
{sdkdir}/frameworks/libs/automation*.swc
{sdkdir}/frameworks/libs/datavisualization.swc
{sdkdir}/frameworks/locale/en_US/automation*.swc
{sdkdir}/frameworks/locale/en_US/datavisualization_rb.swc
{sdkdir}/frameworks/locale/ja_JP/automation*.swc
{sdkdir}/frameworks/locale/ja_JP/datavisualization_rb.swc
{sdkdir}/frameworks/rsls/datavisualization_3.0.0.477.* (or updated build numbers for later builds)
{sdkdir}/fbpro (if you care about source)
Adding to Christophe, you can also roll your own charting component. It's not that hard.