Hi Tricia - did you ever come up with a solution as we are running into the same issue.
This has been discussed a ton on the Fund Services Listserv (www.fundsvcs.org). More and more places are using a pledge form which asks donor to specify how they intend to pay their pledge (personal funds, private foundation, donor advised fund, United Way, matching gift company, etc.) so you can properly record pledges.
Anything not directly coming from personal funds shouldn't be recorded as a personal pledge. To record a pledge from a private foundation or DAF a representative from the foundation will need to sign the pledge form. Some private foundations may but rarely will a DAF so you can not record a pledge at all. Once the money is received you can soft credit the original donor but can not use the payment to satisfy a personal pledge.
Some auditors do not even allow you to create a pledge then write it off when the DAF payment comes in so you have a placeholder for that "pledge". You should check with your auditors on their preference.