This is something of a problem if you're writing for a venue that insists on page numbers. Section 71 of the BW 9 Help system is titled "Bibliography Entries," and includes examples in Chicago and MLA style, which could likely be adapted to Turabian. The Chicago footnote format for BDAG is:
Walter Bauer, A Greek-English Lexicon of the New Testament and Other Early Christian Literature, ed. Frederick W. Danker, 3rd ed. (Chicago: University of Chicago Press, 2000), BibleWorks. v.9.
This doesn't allow for page numbers, and unless you can consult a print version (and if so, what's the point of BW?) you have to resort to something like the old-fashioned "s.v." (for "sub voce," meaning "under the word [in question]") or be creative with something like "see the entry for X."
Having said that, I'm a little pleased with myself to see that a more authoritative source agrees. The Chicago Manual of Style 16th edition has this to say regarding "Publications available in more than one medium" (sec. 14.10; emphasis added): "In many cases the contents of the print and electronic forms of the same publication are intended to be identical.... In practice, because there is always the potential for differences, intentional or otherwise, authors should cite the version consulted. Chicago recommends including a URL or DOI to indicate that a work was consulted online; for other nonprint items, the medium should be indicated (e.g., CD-ROM)." This is what the CMS-based BW format given above does. As to page numbers, CMS 14.17 ("Page numbers and other locators") says in part, "Electronic sources do not always include page numbers (and some that do include them repaginate according to user-defined text size). For such unpaginated works, it may be appropriate in a note to include a chapter or paragraph number (if available), a section heading, or a descriptive phrase that follows the organizational divisions of the work."
I hope that's helpful. You might also want to look at Turabian for the comparable recommendations under these circumstances.
BTW, I would recommend to any scholar or writer who can afford it getting a subscription to the Chicago Manual of Style online, which is my source for the information above. Besides the entire contents of the 15th and 16th editions (searchable), there is a style Q&A (available to non-subscribers), a forum, and other tools. Individual subscriptions are $35/year, and libraries and other institutions can subscribe on a sliding scale of fees. See http://www.chicagomanualofstyle.org/, with a link from there to subscription information.