You can add keywords to access the individual components within the mailbox as necessary. The following are all valid URL values in Netscape:
Each of these will spawn an additional window as required to display the relevant folder within the mailbox. Note that embedded spaces must be URL escaped for them to work. This mechanism does not seem to provide access to sub-folders.
Although Netscape 6.0 supports this request method, its support is incomplete as of the first non beta release.