How Can I Model Individual Bonds Held Within an IRA?

I'm considering buying some individual bonds and holding them until maturity within an IRA. I can't figure out the best way to model this within ESP.

I could just use one of the canned bond assets, I suppose, but since I can know the specific rates of returns as well as maturity dates and amounts, it would be more accurate if I could somehow model this.

If I could contribute to the IRA after beginning withdrawals, I could simply model the interest payments and maturity as "contributions", but the program won't let me do this.

If the bonds were held in a taxable account, I could model the interest payments and maturity as Special Receipts, though I'm not sure how I would model the maturity of a bond bought at a premium. The maturity of a bond bought at a discount could be modeled as two Receipts, the Price as a non-taxable receipt, and the remainder (Par-Price) as a taxable receipt. But a bond bought at a premium will generate a capital gains loss when it matures, and I'm not sure how I would model that. But it doesn't matter, because I'm not holding the bonds in a taxable account, anyway.

I thought maybe I could model this by "anuitizing" some of my retirement, but even if I could figure out how to do this, it would only handle one bond.

Any suggestions?