hmm... here's something i googled...
Property Ownership in Mexico
OVERVIEW
The laws of property ownership in Mexico have changed, allowing non-Mexican citizens to have property rights similar to those in the U.S. and Canada. These rights are executed through a real estate trust in which the title is held. Since foreigners are not able to enter directly into contracts to buy coastal real estate, they must have a bank act on their behalf, much as a trust is used to hold property for minors because they also can not contract. The following is a brief outline of the law regarding such trust, known as a "fideicomiso", (FEE-DAY-E-CO-ME-SO) but potential buyers should always get advice and have all real estate transactions reviewed to their satisfaction.
The Mexican Constitution prohibits direct ownership of real estate by foreigners in what has come to be known as the "restricted zone." The restricted zone encompasses all land located within 100 kilometers (about 62 miles) of any Mexican border, and within 50 kilometers (about 31 miles) of any Mexican coastline. However, in order to permit foreign investment in these areas, the Mexican government created the "fideicomiso" which is, roughly translated, a real estate trust.
A "fideicomiso" is a trust agreement created for the benefit of a foreign buyer, executed between a Mexican bank and the seller of property. The bank acts on behalf of the foreign buyer, holding title to real property. The bank, as trustee, buys the property for the buyer, then has a fiduciary obligation to follow instructions given by the buyer who is the trust beneficiary. The trust beneficiary retains and enjoys all the rights of ownership while the bank holds title to the property. The buyer is entitled to use, enjoy and even sell the property held in trust, at its market value, to any eligible purchaser. The trust lasts 50 years and is perpetually renewable. The beneficiary has a contractual right under the trust agreement with the Mexican bank to all benefits that may result from the use or sale of that property, even though he or she does not hold title to the property. Under Mexican Law, the bank, as trustee, has a fiduciary obligation to respect the rights of the beneficiary.