As in:

"You can give your Lawyer or anyone else a specific power of attorney to sign ... drawn up (contrato promessa de compra e venda) to be signed by you and the seller. ... if a clause of specific execution is included, the vendor cannot .... off against any double taxation agreements in place with yours home country. ..."
www.vernon-algarve.com/cerronovo/buyers.asp

No. 6 January 2007
subject to liability arising from such breach. The legal remedy of specific enforcement (“execução especifica”) established by law, is exceptional in ...
www.garrigues.com/download/Global Newsletter Nº 6.pdf - Similar

Ex: The present pledge agreement is subject to specific limits

--------------------------------------------------
Note added at 1 hr (2009-08-28 13:44:20 GMT)
--------------------------------------------------

"Specific performance" should also be considered for this translation.

Ex.: Specific performance http://en.wikipedia.org/wiki/Contract#Specific_performance

There may be circumstances in which it would be unjust to permit the defaulting party simply to buy out the injured party with damages. For example where an art collector purchases a rare painting and the vendor refuses to deliver, the collector's damages would be equal to the sum paid.

The court may make an order of what is called "specific performance", requiring that the contract be performed. In some circumstances a court will order a party to perform his or her promise (an order of "specific performance") or issue an order, known as an "injunction," that a party refrain from doing something that would breach the contract. A specific performance is obtainable for the breach of a contract to sell land or real estate on such grounds that the property has a unique value. In the United States by way of the 13th Amendment to the United States Constitution, is only legal "as punishment for a crime whereof the criminal shall be dully convicted."[72]

Both an order for specific performance and an injunction are discretionary remedies, originating for the most part in equity. Neither is available as of right and in most jurisdictions and most circumstances a court will not normally order specific performance. A contract for the sale of real property is a notable exception. In most jurisdictions, the sale of real property is enforceable by specific performance. Even in this case the defenses to an action in equity (such as laches, the bona fide purchaser rule, or unclean hands) may act as a bar to specific performance.

Related to orders for specific performance, an injunction may be requested when the contract prohibits a certain action. Action for injunction would prohibit the person from performing the act specified in the contract.